Question

In the right-angled ∆LMN, ∠ M = 90°. If l(LM) = 12 cm and l(LN) = 20 cm, find the length of seg MN.

Answer 1

In the right angled triangle LMN, ∠M = 90^∘. Hence, side LN is the hypotenuse.
According to Pythagoras' theorem,
l(LN)² = l(MN)² + l(LM)²
⇒(20)² = l(MN)² + (12)²
⇒400 = l(MN)² + 144
⇒l(MN)² = 400 − 144
⇒l(MN)² = 256
⇒l(MN)² = (16)²
⇒l(MN) = 16
∴ Length of seg MN = 16 cm.