The answer is the store has 240 melons.
(30x4)x2=240
First look at the given numbers, especially 123 degrees which if you add up the other side it equals 180 degrees so:
180-123= 57
Ok now you know two sides of the triangle and you know that all the 3 sides add up to 360 degrees so:
57+75= 132
180-132= 48
