Let a, b and c are the sides of triangle and s is t
he semi - perimeter, then its area is given by:
A = \(\sqrt{s(s-a)(s-b)(s-c)}\)where s = \(\frac{a+b+c}2\)[Heron’s Formula]
s = \(\frac{a+b+c}2\) = \(\frac{13+14+15}2\) = 21
A = \(\sqrt{21(21-13)(21-14)(21-15)}\)
A = \(\sqrt{21\times8\times7\times6}\) = 84 cm2
Therefore area of ∆ = \(\frac{1}2\)(Base x Altitude)
84 × 2 = 14× Altitude
Altitude = 12 cm