In parallelogram ABCD, AB = 16 cm, BC = 12 cm and diagonal AC = 20 cm. Find the area of the parallelogram ABCD.
192 cm2
s = 20+12+162.
=24
Area of Δ ABC =√s(s−a)(s−b)(s−c)
Δ=√24(24−20)(24−12)(24−16).
=96 cm2
Area of parallelogram = 2 × ΔABC
= 2 × 96
= 192 cm2