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: $PQ = 7, QR = 24, PR = 25$.

(D) In $\Delta PQR$,the side lengths are $PQ = 7$,$QR = 24$,and $PR = 25$.
The longest side is $PR = 25$.
Calculate the square of the longest side:
$PR^2 = 25^2 = 625$
Calculate the sum of the squares of the other two sides:
$PQ^2 + QR^2 = 7^2 + 24^2 = 49 + 576 = 625$
Since $PQ^2 + QR^2 = PR^2$,the triangle satisfies the converse of the Pythagoras theorem.
Therefore,$\Delta PQR$ is a right-angled triangle,and the angle opposite to the hypotenuse $PR$,which is $\angle Q$,is the right angle.