Q11 of 14 Page 206

Find the cost of watering a trapezoidal field whose parallel sides are 10 m and 25 m respectively and the perpendicular distance between them is 15 cm and the rate of watering is Rs. 4 per meter square.

We have to find the area of the trapezoidal field first then the rate of watering

∴ As given


Parallel sides = 10m and 25m.


Distance between these two sides = 15cm = 0.15m.


(∵ 1cm =


⇒ 1cm = 0.01 m)


Area of trapezium is given by


= ×(sum of parallel sides)×(distance between them)


=


=


= 2.625m2


Total cost = Area of field rate of watering


Total cost = 2.625 4


Total cost = Rs. 10.5


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