Question

A sphere has a radius of 2x +5. Which polynomial in standard form best describes the total surface area of the sphere? Use the formula S=4πr^2 for the surface area of a sphere.

A.16πx^2+80πx+100π
B. 16πx^2-80πx-100π
C. 16πx^2+80πx-100π
D. 16πx^2-80πx+100π

Answer 1

A

Explanation:

Using the formula for the surface area with r = 2x + 5, then

S = 4πr²

= 4π(2x + 5)² ← expand the factor

= 4π( 4x² + 20x + 25) ← distribute parenthesis by 4π

= 16πx² + 80πx + 100π → A