Question

Please answer fast................

Answer 1

s=15+17+8/2=20
area= √20×20-17×20-15×20-8
=√20×3×5×12=60cmsq.

Answer 2

The area could be known by using Heron's theorem.

s = (8+15+17)/2 = 20 cm
Δ² = s (s-a)(s-b)(s-c) = 20 * 3 * 12 * 5 
Δ = 60 cm²

It is simpler for a right angled triangle.  Given triangle is right angled.
SO area  = 1/2 * 8 * 15 = 60 cm²