Question

the base of a cylinder has a radius of 9 centimeters. the cylinder is 12 centimeters tall. what is the approximate lateral area of the cylinder? use 3.14 for π and round to the nearest whole number. 108 cm² 339 cm² 678 cm² 972 cm²

Explanation:

Step1: Recall lateral - area formula

The formula for the lateral area of a cylinder is $L = 2\pi rh$, where $r$ is the radius of the base and $h$ is the height of the cylinder.

Step2: Substitute given values

Given $r = 9$ cm and $h = 12$ cm, and $\pi=3.14$. Substitute these values into the formula: $L=2\times3.14\times9\times12$.

Step3: Calculate the result

First, $2\times3.14 = 6.28$. Then, $6.28\times9 = 56.52$. Finally, $56.52\times12=678.24$ $cm^{2}$.

Step4: Round to the nearest whole number

Rounding $678.24$ to the nearest whole number gives $678$ $cm^{2}$.

Answer:

C. $678$ $cm^{2}$