y = 9 ⇒ 2(9) - 3 = 18 - 3 = 15 Congruent with the hypotenuse of Δ DUM x = 12 ⇒ 0.5(12) + 6 = 6 + 6 = 12 Congruent with the short leg of Δ DUM
SAS postulate states that two triangles are congruent if 2 of its sides and 1 angle have equal measure. Both the hypotenuse and short leg are equal in measure. Thus, both triangles are congruent with each other.