Q12 of 99 Page 267

The length of each equal side of an isosceles triangle is 20 m and the angle included between them is 45°. Let us write by calculating the area of triangle.

Given, length of equal sides of triangle = 20m


Angle between the equal sides = 45°


Area of a isosceles triangle with two equal sides and angle between them


= , where s is the length of equal sides and θ is the angle between them


Here


Area of isosceles triangle =


= (∵)


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10

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(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.


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If the perimeter of an isosceles right-angled triangle is (√2+1) cm. Let us write by calculating the length of hypotenuse and area of triangle.