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Question
There is a slide in the park. One of its side walls has been painted in some colour with a message “KEEP THE PARK GREEN AND CLEAN” (see the given figure). If the sides of the wall are 15m, 11m, and 6m, find the area painted in colour.
Solution
It can be observed that the area to be painted in colour is a triangle, with sides of 11 m, 6 m, and 15 m.
Perimeter of such a triangle = (11 + 6 + 15) m
2 s = 32 m
s = `32/2 m`
s = 16 m
By Heron’s formula,
Area of Triangle = `sqrt(s(s-a)(s-b)(s-c))`
= `[sqrt(16(16-11)(16-6)(16-15))]m^2`
= `(sqrt(16xx5xx10xx1))m^2`
= `20sqrt2m^2`
Therefore, the area painted in colour is `20sqrt2m^2`.
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