The sides of a triangle are 3 cm, 4 cm, 5 cm.  The area (in cm²) of triangle formed by joining mid points of this triangle is?

\(\frac{3}{2}\) cm²

Mid point theorem:

Area of Δ DEF = \(\frac{1}{4}\) × area of Δ ABC

ATQ,

Area of Δ ABC = \(\frac{1}{2}\) × BC × AB

                       = \(\frac{1}{2}\) × 4 × 3 = 6 cm²

Now,

Area of Δ DEF = \(\frac{1}{4}\) × area of Δ ABC = \(\frac{1}{4}\) × 6 = \(\frac{3}{2}\) cm²