Help me please , I don’t get how to do this

Me. drysdale earned 906.25 in interest in one year on money that he had deposited in his local bank if the bank paid an interest rate of 6.25% how much money did mr. drysdale deposit

What is the value with a place of tenths in 907.456 1) 0 2) 6 3) 4 4) 5

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.