Year-4 Geometry.pptx

Year 4 - Geometry
 A. Identify two dimensional and three dimensional
shapes
 B. Count and Compare sides vertices and edges
 C. Polygon – Basic, Regular, Irregular
 D. Line, Line segment and Rays
 E. Angles greater than, or equal to right angle
 F. Acute, Right and Obtuse angles
 G. Acute, Obtuse and Right triangles
 Scalene, Isosceles, and Equilateral triangles
 Perimeter of rectangles, Polygons and Rectilinear
shapes

Two Dimensional & Three Dimensional Shapes
Maths | Year 4
Sarah asked teddy to play with shape. She recalled that 2-D
shapes are flat shapes with length and breadth only,
whereas 3-D shapes are not flat they are wide and have a
volume.
Do you know 3D shapes has faces which are 2D shapes? Let’s
find out.
Has a curve face. Has 4 triangle
faces and 1 square
at the bottom.
Has 2 circle faces
at top and bottom,
and 1 rectangle
face.

2D & 3D shapes
Maths | Year 4
Workout the no. of faces/2D
shapes, vertices and edges in the
3D shapes drawn below.
Cone
1 1
1 curved
Face, 1
Circle face
Shapes Name Faces Vertices Edges

2D & 3D shapes
Maths | Year 4
Find which statement is true or false
for the shapes:
I am a hexagonal pyramid. I have 6
triangular faces and 1 square face at the
bottom.
True False
I am ellipsoid. I am volumetric shape
for ellipse.
True
False
I am octahedron. I have 7 triangular
faces.
True False

2D & 3D shapes
Maths | Year 4
I am pentagonal prism. I have five square
faces.
True False
I can turn in to triangular prism. I have
two triangle faces.
True False
I am a trapezoid. I have 6 faces.
True False
I am a diamond and has one curved face
I have no triangle face.
True False

2D & 3D shapes
Maths | Year 4
Hurrah! Now I know many 3D shapes
with different 2D faces. I can draw with
the hints.
1. Draw a 3d shape with minimum two triangular faces. One is
drawn below think from your own also.
2. Draw a 3d shape with minimum two rectangular faces. One is
drawn below think from your own also.
3. Draw a 3d shape with a pentagon face. One is drawn below
think from your own also.

2D & 3D shapes
Maths | Year 4
Find odd one out in each question.
1.
2.
3.
4.
5.
6.

Polygons – Basic, Regular & Irregular
Maths | Year 4
Pentagon
Polygons are flat 2d closed shapes with
straight sides and planes.
No curved side or curved face. Poly means
“many” so it can be 3 or more.
Types of Polygons:
There are two types of Polygons, Regular & Irregular
Polygons.
Regular Polygons are the polygons having all the sides and
angles are equal, such as rectangle, square, pentagon etc.
Rhombus Rectangle
Irregular Polygons are the polygons having indefinite shape
with unequal sides and angles.

Regular Polygons & Irregular Polygons
Maths | Year 4
Let’s have fun with polygons!
Join the dots to close the shape
and find out that is it a regular or
irregular one.

Maths | Year 4
Learn the same sides/edges
polygons; a regular and irregular
and to name them.
Quadrilaterals are the polygons having four sides. Circle all the
quadrilaterals below and tick the regular quadrilaterals.
Pentagons are the polygons having five sides. Circle all the
pentagons below and tick the regular pentagons.
Hexagons are the polygons having six sides. Circle all the
hexagons below and tick the regular hexagons.

Maths | Year 4
Octagons are the polygons having eight sides. Circle all the
octagons below and tick the regular octagons.
Triangles are the polygons having three sides. Circle all
triangles below and tick the regular triangles.
Decagons are the polygons having ten sides. Circle all the
decagons below and tick the regular decagons.
Heptagons are the polygons having seven sides. Circle all the
heptagons below and tick the regular heptagons.

Maths | Year 4
Polygons are fun, lets find the regular and
irregular polygons in the pictures below
and workout the edges and vertices of
them.
a. b. c. d.
e. f.
g.
h.
i. j. k. l.
Mark √ for the shapes that are regular and × for irregular
polygons. Write down the number of sides and
vertices/corners for all.
a) √
Sides : 4
Vertices : 4
b) c) d) e) f)
g) h) i) j) k) l)

Maths | Year 4
Polygons have many sides; in some
shapes they are parallel in some they
are intersecting and in some they are
both. Let’s recall parallel and
intersecting lines.
Parallel lines are the lines
that spaced at same
distance throughout and
never meet or collide with
each other.
Intersecting lines are the
lines that spaced at
irregular distances and at
one point meet or collide
with each other.

Maths | Year 4
Hexagon has 3 pair of parallel sides; each
pair is marked with different color.
Now I know parallel lines are
the opposite lines or sides in
the shapes that never meets.
Let’s find the parallel sides in
the polygons.
Mark parallel sides with different colors for each shape
and write in the shape no. of parallel lines.
3

Maths | Year 4
Find the polygons in real world objects
and count the sides in 2D shape and
corners of the polygon.
Sides / Edges:
Corners:
Sides / Edges:
Corners:
Sides / Edges:
Corners:
Sides / Edges:
Corners:
Sides / Edges:
Corners:
Sides / Edges:
Corners:

Line, Line segment and Rays
Maths | Year 4
We are walking in a line..
Yeyyyy!!! But what is a line?
Let’s learn about point, line, line
segments and rays.
Point is a position or location with no shape and size.
Line is a straight path crossing one or more points; with arrows
on both end. Arrow shows continuation.
Line segment is a straight path between two points; a fixed
distance or measure.
Rays are a straight path having one fixed end and other is never
ending; with arrow on continuity end.
A B C D
BC is line segment, AD is line, A is a ray.

Maths | Year 4
I know what is line, line segment and
rays, now I can find them.
Identify each figure as point, line or line segment. Name them:
Find the number of line segments in each plane shape.

Maths | Year 4
The drawings that we made are composed
of points, lines, line segment and rays.
Find them and label them in the given
picture.

Maths | Year 4
We are champs with shapes
let’s investigate the lines,
line segments and rays in the
shapes below.
A
B
C
D
A’ B’
C’ D’
AB ____________
A’C’ line segment
C’D_____________
A’______________
A
B
C
D
E
F
A’ B’
D’
C’
E’
F’
AB ____________
A’F____________
B’E’____________
B _____________
EF ____________
B’D____________

Maths | Year 4
Do you know shapes and figures
are made of many line segments.
Count the line segments in the
shapes and figures below. State
the parallel line segments also.
No. of line segments 4
Parallel AB and CD
No. of line segments ____
Parallel ____________
Parallel ____________
Parallel ____________
Parallel ____________

Angles and Right Angle
Maths | Year 4
An angle is formed by two line segments
with common end points “or” angles are
turns.
An angle can also be formed when two sides
of a figure meet.
Let’s recall whenever
we move our arms,
we make angles.
There are types of angles with respect to a complete rotation.
Right angle is measured as 90° that is a quarter turn. Whereas a
half turn is straight angle that is 180 ° .

Angles and Right angles
Maths | Year 4
Angles that are less than a quarter turn
are less than right angle and angles
that are more than the quarter turn
are greater than right angle.
Let’s find the angles equal to right angle, greater or
less than right angle.
Angle E is equal to right angle.
Angle F is less than right angle.
Angle G is greater than right angle.

Maths | Year 4
Now I had recalled the basics of angle I
can find out the angles greater, less
than or equal to right angle.
a) b) c)
d) e) f)
g) h) i)
A
B

Maths | Year 4
The needles of the clock follow
turns to show the hours. Be a spy
and find angles less than equal
to or greater than right angles.

Maths | Year 4
Let’s find the angles in the real world.
Find out the right angle less than,
greater than or equal to right angle.

Angles and Right Angles
Maths | Year 4
Edges of 2D and
3D shapes also
form angles. Look
at the figures and
workout the
number of right
angles in it.

Acute, Obtuse and Right Angles
Maths | Year 4
Angles less than or greater
than right angle have names.
Angles that are less than 90°, when measured are Acute
angle.
OR
Angles that are less than a quarter turn i.e. Right angle are
Acute Angles.
Angles that are more than 90° and less than 180°, when
measured are Obtuse angle.
OR
Angles that are more than a quarter turn i.e. Right angle
and less than a half turn i.e., straight angle are Obtuse
angle.
Acute angles
Obtuse angles

Maths | Year 4
Let’s learn how to make
angles with correct
measurements on paper.
We use protractor to draw acute, obtuse and right angles.
Step 1: Draw a line and mark a point on the line called vertex.
Step 2: Place the base line of the protractor on the line drawn
and center of the base line on the vertex.
Step 3: Use an inner scale and outer scale to measure 70°, 90°,
145° etc.

Maths | Year 4
That’s an acute angle.

Angle, Obtuse and Right Angles
Maths | Year 4
We know angle is a
measure of turns also let’s
find out the turns for all
the major angles.
1. If a quarter turn of a complete
rotation is right angle what is the
fraction and degrees for it.
¼ , 90°
2. If a half turn of a complete rotation
is straight angle what is the fraction
and degrees for it.
3. What is the 3/4th turn of a complete
rotation in degrees? The angle is called
reflex angle.
4. What is the full turn of a complete
rotation in degrees? It’s a circle.

Maths | Year 4

Maths | Year 4
We can even read the
time in the no. of turns
or with respect to the
type of angles.
¼ turn, right
angle

Maths | Year 4
Spy the type of angle
and write the measure
of degrees for it.

Maths | Year 4
A
B
C
Make acute angles and obtuse
angles with the help of
protractor.
<A or <BAC = 80°
1. <ABC or <B = 45°
2. <DEF or <E = 76°

Maths | Year 4
Continuing making angles with
protractor and identify them
as acute, obtuse and right
angle.
3. <GHI or <H = 105°
4. <PQR or <Q = 20°
5. <FGH or <G = 140°

Maths | Year 4
In the polygons below the
interior angles are written. Find
out how many obtuse or acute
angles in each polygon.

Acute, Obtuse and Right Triangles
Maths | Year 4
Let’s learn triangles with angles.
Triangles are of different types. They are three sided
polygons but with different interior angles.
A triangle having all the interior angles less than 90°;
acute angles is called Acute Triangle.
A triangle having one interior angle more than 90°;
obtuse angle is called Obtuse Triangle.
A triangle having one interior angle equal to 90°; right
angle is called Right Triangle.

Maths | Year 4
Classify the triangles as right, obtuse and acute
angles. Measure the interior angles with
protractor.
Right

Maths | Year 4
Make triangles by joining these
intersecting rays with respective
angle and classify the triangle by
its interior angles.
1) Not possible 2) 3) Acute triangle
4) 5) 6)
7) 8)

Maths | Year 4
Circle all the triangles that are right triangles.
Triangle Facts
Sum of all the interior angles
of the triangles is 180°. Check
in all the triangles drawn
below.

Maths | Year 4
With the triangle fact let’s
find out the missing angles
of triangles.

Maths | Year 4
Spy the right, obtuse and
acute triangle in the real-
world objects.

Scalene, Isosceles and Equilateral Triangles
Maths | Year 4
We have learned the classification of angles
by angles. Now learn the classification of
triangles by sides.

Maths | Year 4
Which of these triangles is scalene, equilateral o
isosceles. Use a scale with centimeters to find it.

Maths | Year 4
Which of two sides are equal lengths?
Which of two angles are equal measures?
Which of two sides are equal lengths?
Which of two angles are equal measures?
Circle the isosceles triangle in the triangles drawn below.

Maths | Year 4
I can draw the
scalene, isosceles and
equilateral triangles.
Draw an equilateral triangle with sides equal to 8cms.
(1cm is a dot-to-dot distance)
Draw an isosceles triangle with two sides equal to 4 cm and one
side 6cm. (1cm is a dot-to-dot distance)

Maths | Year 4
Draw a scalene triangle with base length 5 cm. (1cm is a dot-to-
dot distance)
Draw a right triangle with base length 7 cm. (1cm is a dot-to-dot
distance)

Perimeter of Rectangle, Polygons and Rectilinear Shapes
Maths | Year 4
Ouch! The table’s edges
are so sharp. It hurt me.
Fix the edges by placing some
rubber covering around the
edges of table. How?
Find out the perimeter of rectangular table
and that much quantity of rubber covering is
required.
Perimeter is the sum of all the lengths / sides / edges of any
2D shape.
6cm
6cm
4cm
4cm
Perimeter of Rectangle= 6 + 6 + 4 + 4 =
20cm
3cm
4cm
3cm
Perimeter of Triangle = 3 + 3 + 4 = 10cm
Perimeter of Rectilinear shape =
3 + 10 + 8 + 4 + 5 + 6 = 36 cm

Perimeter of Rectangles
Maths | Year 4
Now you know the
perimeter of the 2D shape.
It’s the distance all the way
a shape go.
Let’s work out the perimeter of
the figures drawn below.
6 cm
6 cm
5 cm
5 cm
2 cm
7 cm 7 cm
2 cm
8 cm
6 cm
12 cm
2 cm
Perimeter = ______________
Perimeter = ______________
Perimeter = ______________ Perimeter = ______________

Perimeters of Polygons
Maths | Year 4
Regular polygons have the
property that there sides are
equal. By keeping in mind, the
polygon fact, workout the
perimeters of all of polygons
below.
3cm 4cm 2cm
4cm
2cm
3cm 5cm
3cm

Perimeter of Rectilinear Shapes
Maths | Year 4
Perimeter of the rectilinear shape =
8 + 8 + 4 + 4 + 4 + 4 = 32cm

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