Question

Difficulty: EasyTriangles and Pythagorean Theorem

The hypotenuse of a right triangle measures 1313 inches, and one of its legs measures 55 inches. What is the length of the other leg?

  1. 1212 inchesAnswer
  2. B
    144144 inches
  3. C
    194194 inches
  4. D
    88 inches

Answer

The length of the other leg is 1212 inches.
The correct answer is found by properly substituting the hypotenuse (1313) and the known leg (55) into the Pythagorean theorem (a2+b2=c2a^2 + b^2 = c^2). Rearranging to solve for the missing leg gives a2=132−52a^2 = 13^2 - 5^2, which simplifies to a2=169−25=144a^2 = 169 - 25 = 144. Taking the square root of 144144 yields 1212.

Step-by-Step Solution

1
Set up the Pythagorean theorem equation (a2+b2=c2a^2 + b^2 = c^2) with the given values.
a2+52=132a^2 + 5^2 = 13^2
The Pythagorean theorem relates the two legs (aa and bb) to the hypotenuse (cc) of a right triangle.
2
Square the known numerical values.
a2+25=169a^2 + 25 = 169
Evaluating the exponents is the first operational step in solving the equation.
3
Isolate the variable term a2a^2 by subtracting 2525 from both sides.
a2=144a^2 = 144
This leaves the squared variable isolated on one side of the equation.
4
Take the square root of both sides to find the length of the leg.
a=12a = 12
The square root is the inverse operation of squaring, yielding the final length.

Key Concept

The Pythagorean theorem (a2+b2=c2a^2 + b^2 = c^2) can be rearranged to find a missing leg by subtracting the square of the known leg from the square of the hypotenuse (a2=c2−b2a^2 = c^2 - b^2).
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