Question

a circular marble tabletop has a diameter of 42 inches. which measurement is closest to the area of the circular marble tabletop in square inches?
a 5540 in²
b 1385 in²
c 132 in²
d 264 in²

Explanation:

Step1: Find the radius

The radius $r$ of a circle is half of the diameter $d$. Given $d = 42$ inches, so $r=\frac{d}{2}=\frac{42}{2}=21$ inches.

Step2: Calculate the area

The formula for the area $A$ of a circle is $A=\pi r^{2}$. Substitute $r = 21$ into the formula: $A=\pi\times(21)^{2}=\pi\times441$. Taking $\pi\approx3.14$, we have $A\approx3.14\times441 = 1384.74$ square - inches.

Answer:

B. 1385 in²