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A right triangle has legs with lengths equal to 10 inches and 9x inches. Its hypotenuse measures (x + 10) inches

What is the approximate value of the hypotenuse?

10 inches
10.25 inches
20.25 inches
81 inches

User Gajus
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1 Answer

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Answer:

hypotenuse = 10.25 inches

Explanation:

using Pythagoras' identity in the right triangle

the square on the hypotenuse is equal to the sum of the squares on the other two sides, that is

(9x)² + 10² = (x + 10)² ← expand using FOIL

81x² + 100 = x² + 20x + 100 ( subtract x² from both sides )

80x² + 100 = 20x + 100 ( subtract 100 from both sides )

80x² = 20x ( subtract 20x from both sides )

80x² - 20x = 0 ( divide through by 20 )

4x² - x = 0 ← factor out x from each term on the left side

x(4x - 1) = 0 ← in factored form

equate each factor to zero and solve for x

x = 0

4x - 1 = 0 ( add 1 to both sides )

4x = 1 ( divide both sides by 4 )

x =
(1)/(4) = 0.25

now, x > 0 , then x = 0.25

substitute x = 0.25 into the expression for the hypotenuse

hypotenuse = x + 10 = 0.25 + 10 = 10.25 inches

User Jinok
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