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प्रश्न
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.
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उत्तर
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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