Trigonometry to find base length of triangle eg 7.5 × cos "a" or 7.5 × sin "b" or 6 tan"a"

Click on the graphic until you find the right quotient. (36xa - 30xb) ÷ (-6x2)

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angles. measure need asap

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?