Question

The volume of a pyramid with square base is 2058 cubic cm. The height of the pyramid is 14 cm. what will be the approximate length of the slant edges of the pyramid?
1. 18 cm
2. 25 cm
3. 23 cm
4. 20 cm

Answer 1

Correct Answer - Option 4 : 20 cm

Calculation:

V = 1/3 × area of base × height

2058 = 1/3 × a² × 14 

⇒ a² = 441

⇒ a = 21 cm

(Slant edge)² = h² + (diagonal of base/2)²

(Slant edge)2 = 14² + (√2 21/2)²

(Slant edge)2 = 196 + 220.5 = 416.5

Slant edge ≈ 20 cm

∴ The approximate value of slant edge is 20 cm.