Question

3. There is a slide in a park. One of its side walls has been painted in some colour with a
message "KEEP THE PARK GREEN AND CLEAN” (see Fig. 12.10 ). If the sides of the
wall are 15 m, 11 m and 6 m, find the area painted in colour.​

Answer 1

Class 9 Maths Herons formula Ex. 12.1 Q3

Given:

⇒Sides: a=15m, b=11m and c=6m

⇒P=15+11+6=32m

©A. Pal_yt

⇒Semi perimeter=S=32/2 , S=16m

⇒A=s(s−a)(s−b)(s−c) (Heron's formula)

⇒A= √[16(16−15)(16−11)(16−6)]

⇒A= √[16×1×5×10]= √800 = 20√2 m²

©A. Pal_yt