SaiBook.us Geometry

Lesson Example Discussion Quiz: Class Homework

Example

Title: Surface area for Cube & Cylinder

Grade: 6-a Lesson: S3-L2

Explanation: The best way to understand geometry is by looking at some examples. Take turns and read each example for easy understanding.

Examples:

The surface area of a cylinder is 264π square cm. If its radius is 6 cm, find its height.

Step 1a

The given cylinder has a surface area of 264π sq cm and a radius of 6 cm.
The formula to solve for the height:
SA = \$2πr^2 + 2πrh\$

$1a$

Explanation: In this step, we discuss the provided values of a radius of 6cm and a surface area of a cylinder of 264π sq.cm.

Step 1b

Now plug the values into the formula:
264π = \$2π6^2 + 2π(6)h\$
264π = 72π + 12πh
Subtract 72π on both sides:
192π = 12πh

Explanation: In this step, we find the height of the cylinder. Now plug in the values into the formula:
\$264π = 2π(6^2)h + 2π(6)6\$. Subtract 72π from both sides to get 192π = 12πh.

Step 1c

Solve for h:
h = \$(192π)/(12π)\$
h = 16 cm
The height of the cylinder is 16 cm.

Explanation: In this step, solve for h: h = \$(192π)/(12π)\$. The height of the cylinder is 16 cm.