ACT Preparation / Unit 14 ACT 1312 short lesson, about 20 seconds
Cylinders
Captions available
The idea
A cylinder's volume is the base area times the height: V = πr²h. Its surface area is two circles plus the wrapped side: 2πr² + 2πrh.
In practice
A can of radius 3 and height 10 holds 90π, about 283 cubic units.
Where people slip
The side unrolls into a rectangle whose width is the circumference, 2πr.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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