The diagonals of three faces of a rectangular parallelepiped that meet at a single corner measure √5 cm, √10 cm, and √13cm. What is the volume of this parallelepiped?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 6 cm3.
Let edges be a cm, b cm, and c cm
⇒ ...(1)
⇒ ...(2)
⇒ ...(3)
Add (1) and (2): a2 + 2b2 + c2 = 5 + 10 = 15
⇒ 13 + 2b2 = 15
⇒ 2b2 = 15 - 13 = 2
⇒ b2 = 1
⇒ b = 1
a2 + b2 = 5 ⇒ a2 + 1 = 5 ⇒ a2 = 4 ⇒ a = 2
a2 + c2 = 13 ⇒ 4 + c2 = 13 ⇒ c2 = 9 ⇒ c = 3
Volume = a × b × c = 2 × 1 × 3 = 6 cm3