Stepwise
Start practisingPractise

JAMB 2017 · UTME · Q38

A right triangular prism is 8 cm8\text{ cm} long. Each triangular end is a right-angled triangle with hypotenuse 5 cm5\text{ cm} and one of the other sides 4 cm4\text{ cm}. What is the volume of the prism?

Worked solution (try it first)
  1. The third side of the triangle, by Pythagoras: 52−42=9=3\sqrt{5^2 - 4^2} = \sqrt9 = 3 cm.
  2. The two shorter sides are at right angles, so the end has area 12×3×4=6 cm2\frac12 \times 3 \times 4 = 6\text{ cm}^2.
  3. Volume = end area × length: 6×8=48 cm36 \times 8 = 48\text{ cm}^3, option B.

Report a problem with this question