Find the area of a triangle whose two sides are 13cm 14cm and perimeter 42cm.

a = 13cm  , b = 14cm ,

 a+b+c = 42

13+14+c = 42

27+c = 42

 c = 42-27

   = 15 cm

Area of triangle = 

  s =  =  = 21

  area = 

  = 

  = 

  = 7*3*2*2

  = 84 cm²