Getting into Solids: Pyramids - ETA hand2mind

Name __________________________________________
GETTING INTO SOLIDS — PRISMS
Worksheet 15: Answer Key
11.2 cm
3.5 cm
4 cm
8.4 cm
Surface Area
Challenge
Your company, Premium Sauce, is going to purchase one
of the two 16 ounce cans shown and fill them with your
secret tomato sauce products. Your task is to determine
which can will minimize the paper that will go
around the can to advertise the secret sauce. Write a
memo to the advertising department informing them of
the dimensions. Describe your process through a series
of clearly shown mathematical steps.
Step 1: I will find the lateral area of the tall right cylinder.
L.A. = 2 π r h
L.A. = 2 π (3.5)(11.2)
L.A. = 78.4 π
L.A. = 246.301 cm 2
Step 2: I will find the lateral area of the short right cylinder.
L.A. = 2 π r h
L.A. = 2 π (4)(8.4)
L.A. = 67.2 π
L.A. = 211.115 cm 2
Step 3: The lateral area that yields the minimum paper is the short right cylinder. There will be a
savings of 35.186 cm 2 of paper for each can.
Step 4: I will now find the dimensions of the lateral area, which is a rectangle. The circumference of
the circle will be the length. I will find circumference using the formula
C = 2 π r
C = 2 π (4)
C = 8 π
C = 25.133
Step 5: The dimensions of the rectangle will be circumference x height. The dimensions are
25.1 cm x 8.4 cm
(The memo written to the advertising department will vary. However, the dimensions should be
the same.)
25.1 cm x 8.4 cm
Solution: ______________________________
27