Suppose your friend's parents invest $10,000 in an account paying 4% compounded annually. what will the balance be after 10years?

In the diagram, the measure of angle 9 is 85° which angle must also measure 85°?

How do i do this activity, is appreciated

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.