Question 40

The area of a square is 100 sq cm, ﬁnd length of its diagonal?

Solution

Let the side of square = $$s$$ cm and diagonal = $$d$$ cm

=> Area of square = $$(s)^2 = 100$$

=> $$s = \sqrt{100} = 10$$ cm

In right triangle of the square, => $$(s)^2 + (s)^2 = (d)^2$$

=> $$(d)^2 = (10)^2 + (10)^2$$

=> $$(d)^2 = 100 + 100 = 200$$

=> $$d = \sqrt{200} = 10\sqrt{2}$$ cm

=> Ans - (A)

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