Question

The perimeter of an isosceles triangle is 380 cm and it’s unequal side is 150 find the area of triangle (by Heron’s formula)

Answer 1

A ≈ 6538.35 cm²

Explanation:

Calculating the area (A) using Heron's formula

A =
`√(s(s-a)(s-b)(s-c))`

where s is the semi perimeter and a, b, c the 3 sides

here

s = 380 ÷ 2 = 190

given perimeter = 380 and unequal side is 150 , then

equal sides = (380 - 150) ÷ 2 = 230 ÷ 2 = 115 cm

then a = 150, b = 115 , c = 115

A =
`√(190(190-150)(190-115)(190-115))`

=
`√(190(40)(75)(75))`

=
`√(42750000)`

≈ 6538.35 cm² ( to 2 dec. places )