Need it right !
jacob calculated the missing side length of one of these triangles using the pythagorean theorem. which triangle was it?

four triangles a, b, c, d are shown from left to right. triangle a has two sides labeled 2 each, and the included acute angle is shown. triangle b has one side labeled as 4 and the other as 2, and the included right angle is shown. triangle c has one side labeled as 2 and the other as 3, and the included obtuse angle is shown. triangle d has one side labeled as 6 and the other as 7, and the included acute angle is shown.

a
b
c
d