In a right-angled triangle the hypotenuse is 2 cm longer than the longer leg, and the shorter leg measures 10 cm. What is the length of the hypotenuse?

Let the hypotenuse be $x$, so the longer leg is $x-2$. Pythagoras gives $x^2=(x-2{)}^2+10^2$, that is $x^2=x^2-4x+4+100$, so $4x=104$ and $x=26$ cm. The sides are 10, 24 and 26 — twice the triple 5, 12, 13. The trap 24 cm is the longer leg rather than the hypotenuse, 13 cm forgets to scale the familiar triple up, and 12 cm just adds 2 to the given leg.