This document contains geometry theorems and concepts explained through pictures taken in and around the author's home. Each slide defines a geometry term like diameter, circumference, or surface area and includes a photo illustrating that term, such as a mirror demonstrating diameter or a basketball used to explain surface area. The author concludes that all information came from their geometry textbook and all photos were taken in their house.

1. Geometry In My World… By: Jocelyn G

2. Theorem 4-1:
If two lines intersect, then
they intersect at exactly
one point.
The red line and the green
line intersect at the pink
point. This picture is my
living room window.

3. Theorem 5-6: Right Angles theorem
The right angle theorem states
that all right angles are
congruent. This means that in
the picture the two blue squares
representing right angles, are
congruent. This makes sense,
because both right angles equal
90 degrees.
This is the tile in my kitchen.

4. Theorem 18-1:
Triangle Angle Sum Theorem: The
sum of the measures of the angles
of a triangle is equal to 180
degrees.
The three green angles in the picture
when added together will equal 180
degrees because it is a triangle. This
picture is a present I gave to my mom
in 3rd grade for Christmas.

5. Theorem 44-1:
This theorem states that if two polygons
are similar, then the ratio of their
perimeters is equal to the ratio of their
corresponding sides.
The corresponding sides of these
polygons are 2:1. The big tissue box has
a perimeter of 72 inches so that means
that the smaller tissues have a perimeter
of 36 inches because if you divide 72 by
2 it is 36 and we divide it by 2 because
the large tissues are twice as big as the
small ones.
These tissues were in my closet to use.

6. Volume of a prism
The volume of a prism is LWH. L
meaning length W meaning width
and H meaning height.
The volume of this suitcase is 3.5
2 feet*1 foot*3.5 feet. So the feet
volume is calculated to be 7
cubic feet.
2 feet
This is my sister’s new suitcase
1 foot
for her trip to Italy.

7. Perimeter of an irregular pentagon
As you can see from the
purple lines in this picture, 2 feet
their are 5 sides to this shape
making it a pentagon. To find
2 feet
the perimeter you find the 2 feet 2 inches
6.5 inches
length of all the sides and add
6.5 inches
them.
This is the counter below
6.5 inches + 2 feet + 2 feet + 6.5 the house phone.
inches + 2 feet 2 inches = 7 feet and 3
inches in the perimeter.

8. Line of Symmetry
A line of symmetry is a line
that divides a plane figure into
two congruent reflected
halves.
The green line in this
picture separated my
closet door into to
congruent halves,
meaning that it is the line
of symmetry.

9. Circumference of a circle
The circumference of a
circle is C=πd So the
circumference of this circle 4 inches
is C=π(4). π can be
substituted with 3.14 so
the equation is C=3.14(4)
which equals 12.56. The
circumference of this circle
is 12.56 feet.
This is a cashew box found in
the cupboard.

10. Lateral area of a cylinder
Diameter is
The lateral area of a cylinder is 3.5 inches
L= 2πrh. In the picture it shows the
diameter being 3.5 inches so to get the
radius you divide by 2. The radius is
1.75 inches. The height is shown as 4
inches. Plug those into the formula and
you get L= 2π(1.75)(4). Using 3.14 as
pi you get L=2(3.14)(1.75)(4).
Altogether this equals 43.96. So the
lateral area of this cylinder is 43.96
square inches.
Height is 4
inches
This is a soup can also found in my
cupboard.

11. Surface area of a sphere
The surface area of a sphere is
S=4πr2 If the radius of this
basketball is 4.5 inches then we
can plug it into the formula.
S= 4π(4.5)2 If we also substitute
3.14 for pi then we get 4(3.14)
(4.5)2 Multiplying that altogether
equals 254.34 square inches for
the basketball’s surface area.
I got this basketball at a Celtic’s game.

12. Parallel lines
Parallel lines are lines in the
same plane that do not
intersect.
The two purple lines in this
picture are parallel.
This is my wood kitchen floor.

13. Nets
A net is a diagram of
the faces of a three-
dimensional figure
arranged in such a
way that the diagram
can be folded to form
the three-dimensional
figure.
This is the net of a Cheez-It box.

14. Center of a circle
The center of a circle is the point inside
a circle that is equidistant from every
point on the circle. The middle of this
lamp is the bulb (circled in purple) since
it is equidistant from every point on the
circle it is the center of this lamp.
This lamp is in my sister’s room.

15. Congruent
Congruent- having the same size
and shape. The two parts of the
sink in the picture are both
exactly the same size and shape
making them congruent.
This is the kitchen sink in
my house.

16. Convex polygon
Convex polygon- A
polygon in which no
diagonal contains points
in the exterior of the
polygon. This TV
represents a convex
polygon as you can see
by the purple diagonals I
drew in. This is the TV in my living room.

17. Cube
Cube- A prism with six
square faces.
This is a flower vase found in
my house.

18. Decagon
Decagon- A ten sided polygon. A
star is a great example of a
decagon. This star is found
2
3
hanging on the back door of my 1 4
house during the holiday season! 10
5
6
9
8 7

19. Diameter
A segment that passes through the
center of a circle and has endpoints
on the circle; the length of such a
segment.
The orange line of this mirror located in
my living room represents the diameter
of the circle

20. Supplementary angles
Supplementary angles are two
angles whose measures have a
sum of 180 degrees. In this
1 2
picture I used Vienna Fingers to
make supplementary angles. If
you look at the picture you can
see that angles 1 and 2 are
supplementary because their
sums add up to 180 degrees ( a
straight line)

21. Adjacent angles
Adjacent angles are two
angles in the same plane with
a common vertex and a
common side, but no
1 2
common interior points. Angle
1 and 2 seen in the picture
have these qualities therefore
they are adjacent angles.
This is a part of a chair in my
kitchen.

22. Conclusion
For this project I got all of my
pictures from items around my
house. All of the information I got in
the slides came from my Saxon
Geometry book you provided us with
in the beginning of the year.