1. Surface Area
If you remove the surface from a three-dimensional figure and lay it out flat, the pattern you make is called a net.
Nets allow you to see all the surfaces of a solid at one time. You can use nets to help you find the surface area of a three-dimensional figure Surface area is the sum of the areas of all of the surfaces of a figure.

2. Rectangular Prism Finding Surface Area Step 1: Flatten the 3-D figure
A rectangular prism will flatten to 6 rectangles.
Depending on the dimensions of the 3-D figure, you will have different size rectangles.

3. Rectangular Prism Finding Surface Area
Step 2: Transfer the dimensions to the 3-D figure
Dimensions: Length – 12 (the longest side) Height – 8 (top to bottom) Width – 4 (front to back)
Rectangular Prism
Height 8
Width 4
Length 12

4. Finding Surface Area Rectangular Prism
Step 3: Transfer the dimensions from the 3-D figure to the flattened figure
Dimensions: Length – 12 (the longest side) Height – 8 (top to bottom) Width – 4 (front to back) 12 4
Height 8
Width 8 4
Length 12 12 4 8 8 4 12 4

5. Finding Surface Area Rectangular Prism
Step 4: Find the AREA for each rectangle. (Length X Width)
Height 8
Width 4 12
Length
12 x 4 4
48 sq units 12
12 x 8 8
96 sq units 12
12 x 4 4
48 sq units 8
12 x 8 8 32
96 sq units 32
8 x 4
8 x 4 4 12 4

6. Add together the areas for each rectangle
Finding Surface Area
Rectangular Prism
Step 4: Find the TOTAL SURFACE AREA for the 3-D Figure
Add together the areas for each rectangle 8 4 12 48
48 sq units 48 96 96
96 sq units 32 32
Total surface area
48 sq units
= sq. units 32
96 sq units 32

7. Cube or Square
A cube or square will flatten to 6 equal squares.

8. Triangular Prism Step 1: Flatten the 3-D figure
A triangular prism will flatten to 3 rectangles and two equal triangles.

9. Triangular Prism Step 2: Transfer the dimensions to the 3-D Figure 10
Base = 4
Height = 6
Hypotenuse = 12
Length = 10 6 6 12 12 10 4 4 10 6
The 2 triangles will form a rectangle 4

10. Triangular Prism 10 10 6 6 12 12 10 6 4 4 10 10 6 12 Step 3: 4 10
Transfer dimensions to Flattened Figure 4 10

11. Triangular Prism 15 15 8 8 10 10
A = 8 x 15 15 8
120 6 6 15 15
A = 10 x 15 8
Step 4:
A = 6 x 8 2 10 24 24
150
Find the area for each rectangle and triangle 6 15
A = 6 x 15 90 6
Step 5:
Write the area inside the specific shape 15

12. Triangular Prism 15 15 8 8
120 10 10 15
150 8
120 90 6 6 15 24 15 24 8
Step 6:
408 =Total surface area 10 24 24
150
Add all the areas for the total surface area 6 15 90 6 15

13. Cylinder Step 1: Flatten the 3-D shape
A Cylinder will flatten to a rectangle and two equal circles.

14. Cylinder r = d 2 Step 2: Transfer the dimensions to the 3-D shape
Diameter 8
Step 3: Transfer dimensions to the flattened shape
Diameter = 8
radius
Length = 4
Height
2Π4 = 8Π
8Π = 25 15
Height 15 15
Height - 15 25
Diameter - 8
Formulas to use: A =
r = 4
r = d 2

15. Cylinder Step 4: Find the area for each shape 8 8 3.14 x 4 x 4 = 5025
Step 5: Add the areas for the shapes 15
25 x 15 15
A = 375 50 50
375
425
= Total surface area 4
A = 50