Below are given the measures of sides $\overline{PQ}$,$\overline{QR}$ and $\overline{PR}$ of $\Delta PQR$. In each case,determine whether $\Delta PQR$ is a right-angled triangle or not. If it is a right-angled triangle,state which angle is a right angle: $PQ = 15, QR = 17, PR = 8$.

(D) In $\Delta PQR$,the side lengths are $PQ = 15$,$QR = 17$,and $PR = 8$.
To determine if it is a right-angled triangle,we check the converse of the Pythagoras theorem.
The longest side is $QR = 17$.
Calculate the square of the longest side: $QR^2 = 17^2 = 289$.
Calculate the sum of the squares of the other two sides: $PQ^2 + PR^2 = 15^2 + 8^2 = 225 + 64 = 289$.
Since $PQ^2 + PR^2 = QR^2$,the triangle satisfies the Pythagoras theorem.
Therefore,$\Delta PQR$ is a right-angled triangle,and the angle opposite to the hypotenuse $QR$ is $\angle P = 90^\circ$.