Q13 of 99 Page 267

The length of each equal side of an isosceles triangle is 20 cm, and the angle included between them is 30°. Let us write by calculating the area of triangle.

Given, length of equal sides of triangle = 20m


Angle between the equal sides = 30°


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 =


= (∵ sin 30° = 1/2 )


= 100 cm2


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