Question

1. which of the following is closest to the circumference of a circle with a radius of 18 feet? a. 113.04 feet b. 226.08 feet c. 1017.36 feet d. 2034.72 feet

mandy made a circular flower garden with a diameter of 7 feet. she wants to put a fence around the outside of the garden. about how much fence does mandy need to buy? (use 3.14 for π.) a. 11 feet b. 22 feet c. 38 feet d. 44 feet

Explanation:

Step1: Recall the formula for the circumference of a circle

The formula for the circumference of a circle is $C = 2\pi r$ (when radius $r$ is given) or $C=\pi d$ (when diameter $d$ is given), where $\pi\approx3.14$.

Step2: Solve the first - type problem (radius given)

Given $r = 18$ feet. Using $C = 2\pi r$, substitute $r = 18$ and $\pi=3.14$. Then $C=2\times3.14\times18= 113.04$ feet.

Step3: Solve the second - type problem (diameter given)

Given $d = 7$ feet. Using $C=\pi d$, substitute $d = 7$ and $\pi = 3.14$. Then $C=3.14\times7 = 21.98\approx22$ feet.

Answer:

For the circle with radius 18 feet, the answer is A. 113.04 feet.
For the circular flower - garden with diameter 7 feet, the answer is B. 22 feet.