Find the lengths form a right triangle ?

Pythagoras' theorem states that a² + b² = c² where c is the hypotenuse and a and B are the other sides so to see whether they form a right angled triangle for the first question you would do:

8² + 6² = c²
64 + 36 = c²
100 = c²
10 = c

However in the diagram it shows that the other side is 9 so this means it does not make a right angled triangle

6^2 + 8^2 = 9^2

36 + 64 = 81

100 = 81.

THIS IS NOT A RIGHT TRIANGLE.

It is acute

A + B = C is something you can use for right triangles. A and B are the smaller angles, and C is the biggest angle. If A + B is bigger than C, then it is an acute triangle. If A + B is less than C, it is obtuse.

This is too long-standing now get out