Name: __________ Per.: _______ Date: ________
Day 10: Surface Area of Triangles and Rectangles
Learning Objective: By the end of this Lesson I will be able to:
______________________________________________________________________________________
______________________________________________________________________________________
Do Now:
Using your BLUE reference sheet name each figure and find its corresponding SURFACE AREA formula.
Name of the Figure
h
w
l
s
Formula for Surface Area
Day 10: Surface Area of Triangles and Rectangles
Use the appropriate formula to calculate the surface area of the rectangular prism below
1) Emma needs to find the surface area to determine how much paper she needs to wrap this
box. How much paper does Emma need to wrap the box?
l= __________ w = _______ h= _________
Show your work.
15 cm
11 cm
8 cm
Answer: ________________cm2
2) Rashid needs to buy some wood to build a box. He must calculate the surface area of the
box to determine how much wood to buy. A diagram of the box is shown below.
How much wood does Rashid need to buy to build the box?
Show your work.
l= __________ w = _______ h= _________
Answer: ________________ft2
3) Keisha wants to paint the entire outside of her storage box shown in the diagram below.
Use estimation to calculate the Total Surface Area in square inches of the storage box.
Show Your Work
l= 12.6 in ≈ 13 in w = _______ h= _________
Answer: ________________in2
4)
Find the surface area of the figure below.
l = ______
w= _______ h= ________
Show Your Work
s = ________ p = ________
20 cm
15 cm
12cm
30 cm
25 cm
Figure is not drawn to scale
Answer: _______________ cm2
5) Using estimation find the surface area of the figure below.
Show Your Work
S ≈ _____________
7.3 ft
7.3 ft
7.3 ft
Answer: _______________ ft2
6) Natalie is wrapping a box that has length 14.8 in., width 15.9 in., and height 12.9 in.
About how much wrapping paper does Natalie need to wrap the box? (use estimation)
7) Joselyn’s bedroom is in the shape of a rectangular prism. She is going to paint the 4 walls –
but not the ceiling or the floor. The room has a length of 9 feet, a width of 11 feet and a
height of 8 feet.
a) Find the surface area of the 4 walls she will be painting.
b) A can of paint will cover 500 square feet. How many cans of paint will she need?
Challenge Problem
Jonathan is going to cover the inside of this basket with material. So, he will cover all the
sides of the basket except for the top.
a) Determine how much material he needs to cover the inside of the basket.
b) Material is sold by the square yard. A square yard is 36 inches x 36 inches. Will 1 square
yard of material be enough to cover the inside of this basket? Explain how you know.
c) Material is usually sold by the yard. However, you can also buy a fraction of a yard
(½ yard, ¼ yard, etc.). Based on your answer from parts a and b, how much material would
you recommend that Jonathan buy? Explain why.
Day 10: Surface Area of Triangles and Rectangles HW
Find the surface area of each prism. Reminder: Use your REFERENCE SHEET to find the formulas!
1)A classroom is 26ft wide, 32 ft long and 9ft high. What is the surface area of the room in square
feet?
2)A swimming pool is 20.6 m long, 8.5 m wide, and has an average water depth of 1.7 m. Find the surface
area of the pool.
3)A refrigerator is 3 ft wide, 2.5 ft deep and 6 ft in length. What is the surface area of this
refrigerator?
4)What is an estimate for the surface area of the rectangular prism below?
8.0 m
3.2 m
6.5 m