Problem
10. Given a square pyramid with a height of \( 21 \mathrm{ft} \) and a volume of 3969 cubic feet, find the length of one side of the square base. Round to the nearest tenth.
Solution
Step 1 ：\(V = \frac{1}{3}Bh\)
Step 2 ：\(B=\frac{3V}{h}\)
Step 3 ：\(s=\sqrt{B}\)
