Name: _________________________________________________
Surface Area: Cylinders
The supermarket around the corner used to sell Grandma’s favorite Mandarin
oranges. For reasons unknown, they no longer do and it really upsets Grandma.
Jackson, a thoughtful young seventh grader, remembers this fact as he’s
thinking of what to get his Grandmother for her 80th birthday party. Cans of
Geisha Mandarin Oranges, of course!
There’s one potential problem, however: Jackson has two cans to wrap but only
has 550 cm2 of wrapping paper. Does he have enough paper to wrap the two cans?
Strategy: To be able to answer the question, what do you need to know? How will you find it?
Challenge # 1:
25 Country points
(First 3 teams)
Using only your ruler to assist you, find the SURFACE AREA of the first can of
oranges. Use any method. (CENTIMETERS!)
Use 3.14 for π if necessary. Round to the nearest tenth.
WORK: Be neat. Use diagrams and formulas to help illustrate and explain your work.
Challenge # 2:
50 Country points
(First 3 teams)
A) Using only your ruler to assist you, find the SURFACE AREA of the
second can of oranges.
Use 3.14 for π if necessary. Round to the nearest tenth.
B) Does Jackson have enough wrapping paper to wrap the two cans?
Explain how you know.
C) Write a formula to represent the total surface area of any
cylinder. Your formula should be in terms of circles, not rectangles!
WORK: Be neat. Use diagrams and formulas to help illustrate and explain your work.
Debrief
In tomorrow’s Math class, Absent Kid will undoubtedly ask the following question:
I get why we use 2πr2 to find
the area of the two bases
(circles), but I don’t understand
where the 2πrh comes from?
Absent Kid
On the separate sheet of paper (just passed out to you), explain why 2πrh is part of the
equation used to calculate the surface area of a cylinder.