Is this a right triangle why or why not?

No, it does satisfy the Pythagorean Theorem  

Step-by-step explanation:

In right triangle a² + b² = c²

Where a and b = legs and c = hypotenuse

The given measures of the legs are 3 and 7 and the given measure of the hypotenuse is √57

Which means that if this is a right triangle then 3² + 7² = √57²

3² = 9

7² = 49

√57² = 57

9 + 49 = 58

we're left with 57 ≠ 58 which is not true, meaning that , that is not a right triangle

Yes because we can see that it has a 90° angle

Step-by-step explanation:

Oops sorry wrong answer

45

step-by-step explanation:

30+15