In a right angled triangle, the square of the hypotenuse is twice the product…

2024

In a right angled triangle, the square of the hypotenuse is twice the product of the other two sides. Then one of the acute angles of the triangle is

  1. A.

    45 degree

  2. B.

    30 degree

  3. C.

    60 degree

  4. D.

    15 degree

Show answer & explanation

Correct answer: A

For a right triangle with legs b and p and hypotenuse h, the Pythagorean theorem gives h2 = b2 + p2. For any two lengths, (b − p)2 = b2 + p2 − 2bp, so b2 + p2 ≥ 2bp, with equality only when b = p.

  1. The given condition is h2 = 2bp.

  2. By the Pythagorean theorem, h2 = b2 + p2, so b2 + p2 = 2bp.

  3. Rearranging: b2 − 2bp + p2 = 0, i.e. (b − p)2 = 0.

  4. This forces b = p — the two legs are equal, so the triangle is an isosceles right triangle.

  5. In this triangle the two acute angles are equal, and together with the 90° right angle they sum to 180°, so each acute angle = (180° − 90°) / 2 = 45°.

Cross-check: with b = p, h2 = b2 + p2 = 2b2 = 2·b·p (since p = b), matching the given condition h2 = 2bp — confirming the result. Equivalently, tan(45°) = opposite/adjacent = p/b = 1, consistent with equal legs.

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