Can someone please explain the solution (given) to this question, especially the area of the triangle opposite the sector, where did they get sine from? And why is it pi-angle on the sides?

Jenny invests $2,000 at an interest rate of 5%. the amount of money, me, in jenny's account after tyears can be represented using the equation ma-2000(1.05). if jenny would have invested the same amount of money at the same interest rate four years ago, the equation representing the amount of money mo. in her account would be represented using the equation! mg = 2000(105)*** which of the following is equivalent to mp? 2000(105) om- 1.05 2000(1.05) mo 1059 mp-2000(1.05) (105) mp - 2000(1.05) + (1.05)