The lengths of the adjacent sides of a right - angled triangle are xcm, (x-1)cm. If the length of the hypotenuse is \(\sqrt{13}cm\), find the value of x

The lengths of the adjacent sides of a right - angled triangle are xcm, (x-1)cm. If the length of the hypotenuse is \(\sqrt{13}cm\), find the value of x

Answer Details

Let's use the Pythagorean Theorem which states that in a right-angled triangle, the square of the hypotenuse (the longest side) is equal to the sum of the squares of the other two sides. Therefore, for this triangle, we have: \begin{align*} (\text{hypotenuse})^2 &= (\text{one side})^2 + (\text{other side})^2 \\ (\sqrt{13})^2 &= x^2 + (x-1)^2 \\ 13 &= x^2 + (x-1)^2 \\ 13 &= x^2 + x^2 - 2x + 1 \\ 0 &= 2x^2 - 2x - 12 \\ 0 &= x^2 - x - 6 \\ 0 &= (x-3)(x+2) \end{align*} We get two values: x=3 and x=-2. However, x must be positive, so we choose x=3 as the correct value. Therefore, the value of x is 3.