One the first set, #1 figure, notice we have two angle tickmarks, so those angles are equal, however, notice at segment AB, is at the border of both triangles, so AB is just the same length for ∡ABC as it's for ∡ADB.
so, we have an Angle, then a Side, and then an Angle, so they're congruent by ASA.
now, on the 2nd set, #2 figure, we have an angle tickmark and a side tickmark, hmmmmm but notice angles 1 and 2, they're just across from each other at that junction, therefore, angles 1 and 2 are vertical angles adn therefore are also equal.
so, we have a Side, then an Angle and then another Side, the triangles are congruent by SAS.
Answer is $506.25. first month is $100, second month is 100 times 1.5 which is 150. thirst month is 150 times 1.5 which is 225. fourth month is 225 times 1.5 which is 337.5 fifth month is 337.5 times 1.5 which is 506.25
