follow the a² + b² = c² formula
The hypotenuse always equal the c
a and b can be the other two numbers and are interchangeable
plug in 5 and 6 into a and b
(5)² + (6)² = c²
simplify
25 + 36 = c²
add
c² = 61
isolate the c, root both sides
c² = 61
√c²= √61
c = √61
Roots are Irrational numbers, and so D) irrational number should be your answer
hope this helps
In loving memory of Malkea