The equation that could be used to find the length of the hypotenuse is:
c² = 6² + 11²
How to use Pythagoras Theorem?
Pythagoras Theorem is defined as the way in which you can find the missing length of a right angled triangle.
The triangle has three sides,
the hypotenuse (which is always the longest),
Opposite (which doesn't touch the hypotenuse) and
the adjacent (which is between the opposite and the hypotenuse).
Pythagoras is in the form of;
a² + b² = c²
Applying it to the triangle given and we have:
c² = 6² + 11²