One of the legs of a right triangle measures 5 cm and its hypotenuse measures 10 cm. Find the measure of the other leg. If necessary, round to the nearest tenth.

1 answer

To find the measure of the other leg of the right triangle, we can use the Pythagorean theorem, which states that:

\[ a^2 + b^2 = c^2 \]

where \(a\) and \(b\) are the legs of the triangle, and \(c\) is the hypotenuse. In this case, we know one leg \(a = 5\) cm and the hypotenuse \(c = 10\) cm. We need to find the length of the other leg \(b\).

Substituting the known values into the Pythagorean theorem gives us:

\[ 5^2 + b^2 = 10^2 \]

Calculating the squares:

\[ 25 + b^2 = 100 \]

Next, subtract 25 from both sides:

\[ b^2 = 100 - 25 \] \[ b^2 = 75 \]

Now, take the square root of both sides to find \(b\):

\[ b = \sqrt{75} \]

We can simplify \(\sqrt{75}\):

\[ b = \sqrt{25 \times 3} = \sqrt{25} \times \sqrt{3} = 5\sqrt{3} \]

Now, we can approximate \(b\) using the value of \(\sqrt{3} \approx 1.732\):

\[ b \approx 5 \times 1.732 \approx 8.66 \]

Rounding to the nearest tenth, we find:

\[ b \approx 8.7 \text{ cm} \]

Thus, the measure of the other leg is approximately 8.7 cm.