You need to use the Pythagorean theory. a² + b² = c². So you would end up with 10²+10²=c². So, 10²=100, therefore you would end up with 200=c². In order to find the length of the hypotenuse, you need to find C. To do this, you need to undo the square and find the square root of 200 and C. So, you would get √200=√c² which would equal 14.1 inches. Then, if needed to check the answer, plug the 10,10,and 14.1 back into the a²+b²=c² and it should make the statement true.
Answer:
Rotation - Twists the shape
Reflection - Flips the shape
Translation - Slides a shape
Dilation - Enlarge or reduces a shape
Congruent - Same shape same size
Rigid Motion - type of transformation that creates congruent figures
Hope this helped. I apologize if any of them are wrong..