Medium
Using Heron's formula, find the area of a triangle with sides 10 cm, 17 cm, and 21 cm.
Explanation
Explanation
Semi-perimeter s = (10+17+21)/2 = 24.0. By Heron's formula, Area = √[s(s-a)(s-b)(s-c)] = √[24.0 × 14.0 × 7.0 × 3.0] = √7056.00 ≈ 84 cm².
PRO TIP
Re-check your working by substituting the answer back into the original question.