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The shorter leg of a right triangle is 5 centimeters less than the other leg. Find the length of the two legs if the hypotenuse is 25 centimeters.

A) 10 cm and 15 cm

B) 15 cm and 20 cm

C) 20 cm and 25 cm

D) 10 cm and 20 cm

User Arabam
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1 Answer

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Final answer:

Using the Pythagorean theorem, the lengths of the two legs of the right triangle are found by solving a quadratic equation derived from the theorem. The two legs are 20 cm and 15 cm long, respectively.

Step-by-step explanation:

The problem involves finding the lengths of the legs of a right triangle when the hypotenuse is given and one leg is 5 centimeters shorter than the other. We use the Pythagorean theorem, which states that in a right triangle, the sum of the squares of the legs (a and b) is equal to the square of the hypotenuse (c). The theorem is represented by the equation a² + b² = c².

Let the longer leg be x cm. Then, the shorter leg is (x - 5) cm. Since the hypotenuse is 25 cm, we can express this as:

(x - 5)² + x² = 25²

Solving for x:

x² + (x - 5)² = 625

x² + x² - 10x + 25 = 625

2x² - 10x - 600 = 0

Dividing everything by 2:

x² - 5x - 300 = 0

Solving this quadratic equation, we find that x = 20. Therefore, the lengths of the two legs are:

  • Longer leg: 20 cm
  • Shorter leg: 15 cm

The answer is options B) 15 cm and 20 cm.

User Doguita
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