Answer:
A: 779 cm²
B: 1837 cm²
Step-by-step explanation:
For both problems, use the formula for surface area of a cylinder:
SA = 2πr² + 2πrh
2πr² is the two bases.
2πrh is the curved surface.
<u>PROBLEM A</u>
"the cylinder is 60 cm long" is h = 60.
If given diameter, you can find "r" by dividing it by 2. d = 2r
Given d = 4, then r = 2.
SA = 2πr² + 2πrh
SA = 2π2² + 2π2(60)
SA = 8π + 240π Add
SA = 248π Exact answer
SA ≈ 779.114978 Answer on calculator
SA ≈ 779 Rounded answer
Remember to include the units.
The surface area is about 779 cm².
<u>PROBLEM B</u>
"80 cm long" h = 80.
"circumference of 22 cm". C = 22. Remember C = 2πr. Find "r".
C = 2πr
22 = 2πr
11 = πr
r ≈ 11/π
SA = 2πr² + 2πrh
SA = 2π(11/π)² + 22(80) Substitute 2πr with the circumference.
SA ≈ 1837.030992 Answer on calculator
SA ≈ 1837 Rounded answer
Remember to include the units.
The surface area is about 1837 cm².
