Answer: Yes, it is a right triangle
Explanation:
Use the pythagorean theorem in order to determine whether this triangle is a right triangle. Plug in the values given in the problem (4, 7.5, and 8.5) into this equation (a^2+b^2=c^2). This gives you 4^2+7.5^2=8.5^2, and this equation is valid because 4^2+7.5^2 does equal 8.5^2.