Page 13 - Math Course 2 (Book 2)

Geometric Surface Area: Cylinders
Mo. 7

Lesson 2 Key Concept

Lateral Area of a Cylinder
KEY CONCEPTS:
1. Find lateral areas of cylinders. If a right cylinder has a lateral area of L square
2. Find surface area of cylinders. units, a height of h units, and the bases have radii
of r units, then L = 2πrh

MO. 7 - L2a 2πr

Lateral and Surface Area h

of Cylinders

Vocabulary A-Z Surface Area of a Cylinder

Let us learn some vocabulary If a right cylinder has a surface area of T square
units, a height of h units, and the bases have radii
of r units, then T = 2πrh + 2πr 2
axis

The axis of the cylinder is the segment with r
endpoints that are centers of the circular bases.

Base h
r

Altitude Axis

Let’s Begin
Base

right cylinder Real World Example
If the axis is also the altitude, then the cylinder is
called a right cylinder. A fruit juice can is cylindrical with
aluminum sides and bases. The can is
12 centimeters tall, and the diameter of
the can is 6.3 centimeters. How many
r square centimeters of aluminum are
used to make the sides of the can?

Altitude Axis
The aluminum sides of the can represent the lateral
area of the cylinder. If the diameter of the can is 6.3
centimeters, then the radius is 3.15 centimeters.
The height is 12 centimeters. Use the formula to
find the lateral area.
right cylinder

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