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Question
In the figure below, find the value of 'x'.

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Solution

In the right-angled triangle PQR,
∠Q = 90°
Hence, side PR is the hypotenuse.
According to Pythagoras' theorem,
l(PR)2 = l(QR)2 + l(PQ)2
⇒ (41)2 = (x)2 + (9)2
⇒ 1681 = x2 + 81
⇒ x2 = 1681 − 81
⇒ x2 = 1600
⇒ x2 = (40)2
⇒ x = 40
∴ The value of x is 40.
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