I will mark brainliest !

90 degrees

Step-by-step explanation:

A circle circumscribed over a right triangle is the same as a circle circumscribed over a rectangle built from the extension of the right triangle.

That tells us that the hypotenuse is the diameter of the circle in that case.

Here, we can see a triangle that has the hypotenuse as the diameter of the circumscribed circle. We can infer that the triangle is a right triangle.

-4

step-by-step explanation:

(-4+8)=-(4-8)=-8+4=-4