Unit 8, Lesson 4 Surface Unit 8, Lesson 4 Surface AreaArea

Standard: MG 3.0Objective: Find the volume and surface

area of prisms and cylinders.

Topic: Surface AreaSurface Area

Definition: Surface Area of a 3-dimensional figure is the sum of all the areas of the the sum of all the areas of the faces.faces.

To find the surface area of any solid figure, , find the area of each face (side), and find the area of each face (side), and add them all together.add them all together.

SURFACE AREATHINK GIFT WRAP! Step 1: Determine the

number of surfaces (sides) and LIST THEM!

Step 2: Use the formulas to calculate the area of each side.

Step 3: ADD the sides together. Remember that AREA is measured in SQUARE UNITS.

5 cm

3 cm

2 cm

TOP:

BOTTOM:

FRONT:

BACK:

RIGHT SIDE:

LEFT SIDE:

b·h = (5)(3) = 15

b·h = (5)(3) = 15

b·h = (5)(2) = 10

b·h = (5)(2) = 10

b·h = (3)(2) = 6

b·h = (3)(2) = 615+15+10+10+6+6 = 62 cm2

CYLINDERS3 in

10 in

2rA

2

2

26.28

)9)(14.3(

)3)(14.3(

inA

A

A

TOP

BOTTOM

SIDE10 in

TOP: 28.26 in2

BOTTOM: 28.26 in2

SIDE: 188.4 in2C=2πr C=2(3.14)(3)

18.84 in2

28.26 + 28.26 + 188.4 = 244.92 in2

SURFACE AREA7 ft

4 ft

6 ft

5 ft5 ft

How many sides?

5

2

hb

212

2

46

ft

235

57

ft

hb

242

67

ft

hb

12 + 12 + 35 + 35 + 42 = 136 ft2

12 ft235 ft2

35 ft2

42 ft2

12 ft2

Example: Find the area of the cube shown.

5 cm

Example: Find the surface area of the rectangular prism shown.

4 in.4 in.

3 in.3 in.

8 in. 8 in.

You try: Find the surface area of the cube.

7 cm7 cm

You try: Find the surface area of the rectangular prism.

5 in.5 in.

2 in.2 in.

10 in. 10 in.

REVIEWREVIEW

1) What is surface area?

2) How do you find the surface area?

3) How is surface area different from volume?