1. Surface area of rectangular prisms
Today’s Lesson:
What:
Surface area of rectangular prisms
Why:
. . . so I can calculate the surface area of rectangular prisms.

2. Why does the SA formula for a rectangular prism have 3 separate parts ?

3. Let’s build a Rectangular prism . . . “Surface Area Net Activity”
(teacher will give directions)

4. Let’s fill in the data from the prism we built . . .

5. The formula explained . . . six bottom left pair SA= 2lw + 2lh + 2wh
There are ____________ faces in a rectangular prism!
The top and ___________________ faces are congruent, the front and back faces are congruent, and the right and _______________ faces are congruent.
This is why there are three separate “clusters” in the SA formula– each represents a congruent ______________ of faces!
six
bottom
Bottom
Left
Back
left
pair

6. Take a look: Surface Area Formula Animated
Website with animated explanation . . .
Surface Area Formula Animated

7. Apply the formula: 1)
SA= 2lw + 2lh + 2wh
12 cm
5 cm
4 cm
SA = 256 cm²

8. SA = 168 cm² Apply the formula: 2) 2 cm 14 cm 3.5 cm
SA= 2lw + 2lh + 2wh
3.5 cm
14 cm
2 cm
SA = 168 cm²

9. Surface area word problem:
Bob is wrapping a present that is 12 inches long, 4 inches
wide, and 3 inches tall. What is the minimum amount of
wrapping paper required?
SA= 2lw + 2lh + 2wh
SA = 192 in²

10. Wrap-it-up/summary:
Why does the SA formula for a rectangular prism
have 3 separate parts ?
Because a rectangular prism has six faces– or 3 PAIRS of congruent faces.

11. Finish homework worksheet (handed out in class).

12. END OF LESSON