As it says that the figure has to be proved by SAS postulate. We know that, SAS stands for Side - Angle - Side, so we need to prove that any two sides and one angle of two triangles are equal/proportional or not.
A pair of tires is $216, so at that rate 4 tires would be $432. The managers special is $380 so $432-$380=$52 savings for 4. $52\4=$13 savings per tire.