A, B and C form the vertices of a triangle. AB = 12cm, AC = 14cm and BC = 16cm. Calculate the area of the triangle rounded to 1 DP.

You can use Heron's formula:

 

Let s = semi-perimeter     s = (12 + 14 + 16)/2 → 21 cm

 

Area = sqrt(s*(s-a)*(s-b)*(s-c))

 

Area = sqrt(21*(21 - 12)*(21 - 14)*(21 - 16)) cm²

 

Area = sqrt(21*9*7*5) → 81.3 cm²