Question

Find the length of the diagonals of a rectangle whose sides are10cm and 8cm

Answer 1

Since it is a rectangle its opposite sides will be parallel and adjacent sides will be perpendicular to each other hence forming an angle of 90° at 4 given vertices.

And when we draw the diagonals, it will divide the rectangle in two equal right angle triangles,

Then according to pythagoras theorem, we get

(diagonal)² = (length)² + (width)²

Length given as = 10 cm

Width given as = 8 cm

SO, (d)² = (10)² + (8)² where d is the diagonal

d² = 100 + 64

d² = 164

d = √164

d = 2√41 cm

Answer 2

Your answer !!

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$First \: side = 10 cm \\ \\ Second \: side = 8 cm \\ \\ {d}^{2} = {l}^{2} + {b}^{2} \\ \\ {d}^{2} = {10}^{2} + {8}^{2} \\ \\ {d}^{2} = 100 + 64 \\ \\ {d}^{2} = 164 \\ \\ d = \sqrt{164} \\ \\ d = 2\sqrt{41}$

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