Answer:
Equal sides: a = b = 12 cm (given)
The formula for the perimeter of a triangle: Perimeter(P) = a + b + c
30 = 12 + 12 + c (Given, perimeter = 30 cm)
c = 30 - 24
c = 6 cm
Now, Semi Perimeter (s) = P/2 = (a + b + c)/2
s = 30/2
s = 15 cm
By using Heron’s formula,
Area of a triangle = √s(s - a)(s - b)(s - c)
= √15(15 - 12)(15 -12)(15 - 6)
= √15 × 3 × 3 × 9
= √1215
= 9√15 cm2
Area of the triangle = 9√15 cm2