Answer:

Step-by-step explanation:
Refer to the attached image.
A right triangle is considered so when one of its corners are 90°.
If sides a and b are equal in length, then the corners across from them are equal in size as well.
The only way for this to be possible is if both corners A and B(opposite of sides a and b) are 45°.
Pythagorean theorem
This theorem states that the square of a right triangle's long side is equal to the sum of the squares of the shorter sides.
In this case:

but since:

the equation can be solved by replacing a with b in the equation:
