# Chapter 10

### Brandon T

## 10.3 - Three-Dimensional Figures!

Pyramid - A polyhedron that has 1 base and the faces are triangles

Cylinder - NOT a polyhedron but has 2 congruent circular bases

Cone - NOT a polyhedron but has 1 circle base

Sphere - NOT a polyhedron but is formed by all points in space that are the same distance from a fixed center

## 10.4 - Finding surface areas of prisms and cylinders!

Use a net to find out the area of all the faces and then add them up

Surface area for a prism

S = 2B + Ph

B = The area of the base

P = The perimeter of the base

Practice:

B = 56

P = 64

h = 7

2 * 56 = 112

64 * 7 = 448

448 + 112 = 560

A = 560

Surface area for a cylinder

2pi * r2 + 2pi * rh

Practice:

r = 5

h = 7

2 * 3.14 = 6.28

6.28 * 5 * 2 = 62.8

6.28 * 5 * 7 = 219.8

219.8 + 62.8 = 282.6

A = 282.6

## 10.5 - Finding the Surface area of cones and pyramids!

S = B + 1/2Pl (LOWERCASE L)

Practice:

B = 32

P = 23

l = 7

23 * 7 / 2 = 80.5

32 + 80.5 = 112.5

A = 112.5

Surface area for a cone

S = pi * r2 + pi * rl

l = slant height

Practice:

r = 5

l = 5

3.14 * 5 * 2 = 31.4

3.14 + 5 * 5 = 28.14

28.13 + 31.4 = 59.54

A = 59.54