Pls help with my math

How can we find the measure of an exterior angle if we know the measurement of an interior angle

5500 dollars is placed in an account with an annual interest rate of 6.5%. to the nearest tenth of a year, how long will it take for the account value to reach 19700 dollars?

Fractions can be added and subtracted only if they're fractions. a. like b. proper c. improper d. unlike