What is the area of a triangle with sides measuring 7 cm, 7.4 cm and 9.6 cm?

Question

Round to the nearest tenth.

 

Area ≈  _?_ cm².

Answer 1

Since this is not a right triangle, it's easier to use Heron's Formula instead of A = 1/2bh.

Heron's Formula says that if the sides of a triangle are a, b, and c then we define the "semi-perimeter" (s) as:

s = (a + b + c)/2

Then we can say the Area of a triangle = √(s(s - a)(s - b)(s - c))

In this case s = (7 + 7.4 + 9.6)/2 = 24/2 = 12

So A = √(12(12 - 7)(12 - 7.4)(12 - 9.6)) = √12•5•4.6•2.4 = √662.4 = 25.73713271

Rounding to the nearest tenth we get A = 25.7 cm²