Unit 10-Day 1Unit 10-Day 1

Squares:Squares:Area and Perimeter Area and Perimeter

Unit 10-Day 1Unit 10-Day 1

Squares:Squares:Area and Perimeter Area and Perimeter Objective: Objective: Find the area and Find the area and

perimeter of a square. perimeter of a square.

Perimeter:the distance around the outside of a figure!

s

s

s

s

Perimeter of Square = s + s + s +s P = # of sides x side

length P = (4)(side length)

P = 4s

Formula:

P = 4s

Perimeter:

Example 1:Find the perimeter of a square with

a side length of 12 cm.

12 cm.

P = 4sP = 4(12)P = 48 cm

Example 2:Find the side length of a square with

a perimeter of 32 cm.

8 cm.

P = 4s32 = 4s4 4

8 = s

Example 3:Find the side length of a square with

sides x +2 and the perimeter 20.

x + 2

P = 4s20 = 4(x+2)20 = 4x + 812 = 4x

-8 -8

x = 3s = x + 2s = 3 + 2s = 5

Practice #1:

2. Find the side length of a square with a perimeter of 216 cm.

3. Find the side length of a square with sides x-3 and a perimeter of 40.

1. Find the perimeter of a square with a side length of 75 cm.

P = 300 cm

s = 54 cm

s = 10

Area: The amount of two dimensional space. (The space inside a figure.)

Area of a square (side length)(side length)

2A s

2A 42A 16 cm

Formula:

4

4

2Area of a square (side length)

Example 3:Find the area of a square with a side

length of 12 cm.

12 cm.

2A s2A (12)

2A 144 cm

Example 4:Find the side length of a square with

an area of 225 cm2.

2A s2225 s

2225 s

15 cms

Take the square root of both sides!

Practice #2:

2. Find the side length of a square with an area of 196 ft2.

1. Find the area of a square with a side length of in.

A = 5 in.2

s = 14 ft.

5

CUBES:CUBES:Surface Area & Surface Area &

VolumeVolume

CUBES:CUBES:Surface Area & Surface Area &

VolumeVolume

Objective: Find the surface area Objective: Find the surface area and volume of a 3-D figure. and volume of a 3-D figure. Objective: Find the surface area Objective: Find the surface area and volume of a 3-D figure. and volume of a 3-D figure.

Surface Area:The total area of the external surface of a three-dimensional figure.

Find one that is a cube!

Cube: Three Dimensional Figure that has six sides that are squares.

Height

Length

Width

• http://www.mathsnet.net/geometry/solid/nets.html

Find one that is a cube!

s

ss

SA = (Area of one square)(# of square)

SA = (s 2)(6)Formula:SA = 6s 2

The total area of the external surface of a three-dimensional figure.

Surface Area:

Example #1: Find the Surface Area of the cube with a side length of 5 ft.

5 ft.

SA = 6 s2

= (6)(5)2

= (6)(25)

SA = 150 ft2

1. Find the Surface Area of the cube with a side length of 10 inches.

2. Find the side length of a cube with a surface area of 864 cm2.

SA = 600 in.2

s = 12 cm.

Practice #1:

Volume: The total amount of space inside a 3 dimensional figure.

S

SS

Volume = (side length)3

V = s 3

Volume = (height)(length)(width)

Formula:

Example #2:Find the volume of the cube with a side length of 4 inches.

4 in.

4 in.4 in.

V = s 3

V = (4)3V = 64 in.3

Example #3:Find the side length of a cube with a volume of 125 cm3.

V = s 3

125 = s 3

s = 5

Take the cube root of each side. 3 33 125 s

3 5 5 5 s

1. Find the Volume of the cube with a side length of 6 inches.

2. Find the side length of a cube with a volume of 27 cm3.

V = 216 in.3

s = 3 cm.

Practice #2: