1. Finding Surface Area Rectangular Prism 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. 1

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

3. 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 3

4. 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 4

5. 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 5

6. You can also use a table, instead of drawing the net.
Since opposite faces are congruent,
you have three pairs of congruent rectangles. 8 4 12
Face
Formula: A = bh
Area
Top
4 x 12 48
Bottom
Left
8 x 4 32
Right
Front
8 x 12 96
Back
Total: 352 sq units 6

7. Group Practice:
Fill out this table on your scratch paper to find the area for this figure.
Face
Formula: A = bh
Area
Top
Bottom
Left
Right
Front
Back
Total: _____ sq units 7

8. CPS Practice: The top and bottom faces each have an area of: A) 64 22456
None of the above
(Fill out a table for this figure as you do each of the next few questions.) 8

9. The left and right faces each have an area of:
224 56
None of the above 9

10. The front and back faces each have an area of:
224 56
None of the above 10

11. The total surface area of this rectangular prism is:
B) 896
C) 344
D) 688 11

12. Cube or Square
A cube or square will flatten to 6 equal squares. 12

13. Triangular Prism Step 1: Flatten the 3-D figure
A triangular prism will flatten to 3 rectangles and two equal triangles. 13

14. Triangular Prism Step 2: Transfer the dimensions to the 3-D Figure 15
Base = 8
Height of Tri. = 6
Hypotenuse = 10
Height of prism = 15 8 8 10 10 15 6 6 15 14

15. Triangular Prism 15 15 8 8 10 10 15 8 4 6 15 15 8 10 Step 3: 6 15
Transfer dimensions to Flattened Figure 6 15 15

16. 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 16

17. 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 17

18. Try using a table instead of drawing a net.15 8 8 15 6 6
Face
A = ½(bh)
Area
Triangle
½ (8 x 6) 24
½(8 x 6)
Rectangle 1
8 x 15
120
Rectangle 2
6 x 15 90
Rectangle 3
10 x 15
150
Total: 408 sq units 18

19. CPS Practice What is the area of each of the two triangles? 48 m²
(Fill out a table for this figure as you do each of the next few questions.) 19

20. The three rectangles have the following areas:
150, 150, 150
150, 100, 100
150, 150, 180
180, 180, 150 20

21. The total surface area of this triangular prism is:
600
576
480
The same as the surface area of the moon. 21

22. Cylinder Step 1: Flatten the 3-D shape
A Cylinder will flatten to a rectangle and two equal circles. 22

23. 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 23

24. 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 24

25. Or, try using a table. 8
Face
A =πr2 or
A = Ch
Area
Circle
π4²
50.25
Rectangle
8π x 15
376.8 15
Total: sq units
Just remember that the circumference of the circle is always one side of the rectangle and the height of the cylinder is the other. 25

26. CPS Practice 5
What is the approximate area of each of the circles in this cylinder?
About 15 sq units
About 30 sq units
About 100 units
About 75 sq units 25 26

27. How do you find the area of the lateral rectangle for this cylinder?
Multiply the circumference of the circle by the height of the cylinder.
Multiply the diameter of the circle by the height.
Multiply the radius by the height.
Multiply any two numbers that you happen to see on the diagram. 5 25 27

28. What is the approximate area of the lateral rectangle?
125 sq units
About 750 sq units
About 75 sq units
About 1,200 sq units 5 25 28

29. The total surface area is about:
750 sq units
825 sq units
900 sq units
The same as a can of Spaghettio’s. 5 25 29