Question

the perimeter of an equilateral triangle is 60mm the area is

Answer 1

perimeter of an equi. triangle is a+b+c is 60 (a=b=c)

a+a+a=60

3a=60

a=60/2

a=30mm

semi perimeter is

perimeter /2

60mm/2

s is 30mm

area of triangle by heron's formula

√s(s-a)(s-b)(s-c)

√30(30-20)(30-20)(30-20)

√30(10)(10)(10)

√3×10×10×10×10

10×10√3

20√3

area of triangle is 20√3