The figure below shows two triangles efg and klm.
which step can be used to prove that triangle efg is also a right triangle?
answer

prove that a + b is greater than c in triangle efg so c2 = a2 + b2.

prove that kl = ef so in triangle klm c2 = a2 + b2 which makes triangle efg a right triangle.

prove that the sum of the squares of a and c in triangle efg is greater than square of b in triangle klm.

prove that the sum of the squares of a and b in triangle klm is greater than square of c in triangle efg.