You can calculate Interest on your loans and investments by using the following formula for calculating simple interest: Simple Interest= P x R x T ÷ 100, where P = Principal, R = Rate of Interest and T = Time Period of the Loan/Deposit in years.
Since the total measure of all the angles of a triangle is always 180, solve for x with the equation: 3x+1+2x-3+9x=180. x=13. Now plug in x and look for the smallest one, which will be B. 23 degrees.