Question 21

What must be the length (in cm) of the diagonal of a rectangle if its area and breadth are 120 cm2 and 8 cm respectively ?

Solution

Let length of rectangle = $$l$$ cm and breadth, $$b=8$$ cm

=> Area = $$8l=120$$

=> $$l=\frac{120}{8}=15$$ cm

=> Diagonal, $$d=\sqrt{l^2+b^2}$$

=> $$d=\sqrt{(15)^2+(8)^2}$$

=> $$d=\sqrt{225+64}=\sqrt{289}$$

=> $$d=17$$ cm

=> Ans - (B)

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