Answer:
it's more ABC
we know the 3 measures
we apply the Pythagorean reciprocal : If in a triangle, the square of the length of the longest side is equal to the sum of engths of the squares of the other two sides then this triangle is right-angled
if AC²=AB²+BC², ABC is rectangle so has a right angle
AC²=17²=289
AB²+BC²=8²+15²=289
--->AC²=AB²+BC², ABC is rectangle so has a right angle ∠B
Explanation: