There is a slide on a park. One of its side walls has been painted in some colour with a message "KEEP THE PARK GREEN AND CLEAN" (see figure). If the sides of the wall are 15 m, 11 m and 6 m, find the area painted in colour.

Since, the shape of painted colour is a triangle.
Let us assume the sides of the triangle are, a=15 m, b=11 m and c=6 m
⇒P=15 m + 11 m + 6 m = 32 m
⇒Semi perimeter = s = 32/2 m = 16 m
Now, lets evaluate the area of triangle by using Heron's formula,
⇒A = √s(s-a)(s-b)(s-c) (Heron's formula)
⇒A = √16(16-15)(16-11)(16-6)
⇒A = √16 × 1 × 5 × 10
⇒A = √800
⇒A = 20√2
Therefore, the area of the painted colour is 20√2 m².