Q10 of 99 Page 267

The length of three sides of a triangular filed of village of Paholampur are 26 meter, 28 meter and 30 meter.

(i) Let us write by calculating what will be the cost of planting grass in the triangular field at the rate of Rs. 5 per sq. meter.


(ii) Let us write by calculating how much cost will be for fencing around three sides at the rate Rs. 18 per meter leaving a space 5 meter for constructing entrance gate of that triangular field.

Given sides of triangle a= 26 m, b = 28m, c = 30m


(i) Since the grass has to be planted within the area of triangular field we will calculate area of the triangular field


Area =


Where s is the semi perimeter of triangle and a, b, c are the sides of the triangle


⇒


⇒ s = 42 cm


Area =


=


=


=336 m2


Cost of planting grass = area of triangular field × rate per sq meter


= 336 × 5


= Rs1680


(ii) Since the fencing is to done on the edges, we will calculate the perimeter of triangular field


Perimeter of triangular field = 26 + 28+30


= 84cm


Since 5 meter space has to be left for entrance gate construction


So the total perimeter to be fenced = 84-5 = 79cm


Cost of fencing the triangular field = perimeter of the field to be fenced × rate of fencing per meter


Cost of fencing = 79 × 18


= Rs 1422


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(i) Let us write by calculating the area of the park.


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