In the ΔABC, ∠B is a right angle, D and E are the mid-points of the sides AB=3 cm and AC=5 cm respectively. Then, the length of DE is
2 cm
In △ABC,
AC2=AB2+BC2 [Pythagoras theorem]
⇒BC2=52−32=25−9=16
⇒BC=√16=4 cm
From mid-point theorem, DE=BC2=42=2 cm