Introduction to Geometry

1. Kurt Shin
Introduction to Geometry
Shape Details
(Geometry Grades 7-8)

2. Objectives & CA
Content Standards
• To familiarize yourself with unique
details about each shape.
• Solve real-world and
mathematical problems
involving area, surface area,
and volume of two- and three-
dimensional objects composed
of triangles, quadrilaterals,
polygons, cubes, and right
prisms.

3. Why is Geometry Important?
• Geometry is the foundation for building or creating anything including
art and buildings.
• Understanding Geometry can help you improve building any kind of
structure, even in games like Fortnite or Minecraft.

4. What is a Square?
• Definition: A regular
quadrilateral, has 4 equal sides
and 4 equal angles.
• How to find the area: Take the
length of a side and square it
• How to find the perimeter: Add
all sides of the square.

5. Squares in Everyday Life

6. What is a Circle?
• Definition: Shape consisting of all points in a plane that
are given distance from a given point, the center.
• How to find the area: Multiply pi by r squared
• How to find the perimeter: Multiply 2 by pi and by r

7. Circles in Everyday Life

8. Now you try!
What is a characteristic of a
square?
a) Has 4 sides
b) All sides are the same
c) All angles are right angles
d) All of the above

9. Now you try!
How do you find the area of a
circle?
a) Pi x diameter squared
b) Pi x radius
c) Pi x radius squared
d) Pi x diameter

10. What is a Triangle?
• Definition: Polygon with three
edges and three vertices.
• How to find the area: ½ base x
height.
• How to find the perimeter: Add
all 3 sides of the triangle.

11. Triangles in Everyday Life

12. What is a Rectangle
• Definition: Quadrilateral with four
right angles. (Fun Fact: Squares are
technically Rectangles)
• How to find the area: Multiply Length x
Width
• How to find the Perimeter: Add the
length of all the sides together

13. Rectangles in Everyday Life

14. What is a Parallelogram?
• Definition: Simple quadrilateral with two
pairs of parallel sides. The opposite sides of
a parallelogram are of equal length and the
opposite angles are of equal measure
• How to find the area: Multiply base x
height
• How to find the perimeter: Add all the
sides together.

15. Parallelograms in Everyday Life

16. Now you try!
How do you find the area of a
triangle?
a) Base x height
b) ½ base x height
c) Add all 3 sides
d) 2 x base x height

17. Now you try!
What is a fun fact about rectangles?
a) Squares are rectangles
b) Rectangles can have 5 sides
c) Not all rectangles have right
angles
d) None of the above

18. Chart of Shapes
and their
Properties

19. Educational Video
• Finding the perimeter of shapes is usually the easier part of measuring a
shape.
• However, finding the area can get confusing. Here are some educational
videos on how to find the area of the shapes we have learned so far.
• https://www.youtube.com/watch?v=xCdxURXMdFY&ab_channel=math
antics
• https://www.youtube.com/watch?v=O-
cawByg2aA&ab_channel=mathantics

20. Culminating Questions
What is the Area of the following Triangle?
a) 15 in.
b) 25 in.
c) 23 in.
d) 21 in.

21. Culminating Questions
What is the Perimeter of the following Circle?
(Round to the nearest tenth)
a) 42.46
b) 29.34
c) 31.42
d) 35.79