Question

The Unisphere is the world's largest man-made globe. It was built as the symbol of the 1964-1965 New York World's Fair. A sphere with the same diameter as the Unisphere globe would have a surface area of 45,239 square feet. What is the diameter of the Unisphere?

Answer 1

$\bf \textit{surface area of a sphere}\\\\ A=4\pi r^2\qquad \begin{cases} r=radius=\frac{diameter}{2}\\ diameter=2r\\ ----------\\ A=45,239 \end{cases}\implies 45,239=4\pi r^2$

solve for "r", to see what the radius is

keep in mind that, the diameter is just "2r"