Question

what is the area of a circle with a diameter of 10 millimeters? estimate the area to the tenths place using 3.14 for $pi$. (1 point)
78.5 square mm
79 square mm
314 square mm
15.7 square mm

Explanation:

Step1: Find the radius

The radius $r$ of a circle is half of the diameter $d$. Given $d = 10$ mm, so $r=\frac{d}{2}=\frac{10}{2}=5$ mm.

Step2: Calculate the area

The formula for the area $A$ of a circle is $A=\pi r^{2}$. Substitute $r = 5$ mm and $\pi=3.14$ into the formula: $A = 3.14\times5^{2}=3.14\times25 = 78.5$ square mm.

Answer:

78.5 square mm