Cary sets up a checking account with an initial balance of $27,700, and the rent for her apartment is deducted every month for a year. After a year the balance is $7900
(Assume no other transactions occur on the account)

$1,650

Step-by-step explanation:

First, we need to find how much she paid the whole year. 27,700-x=7900. If we subtract 7900 from each side and add x to each side, we get 19,800=x. Therefore, she paid $19,800 in rent the whole year. Since there are 12 months in a year, and each month she paid the same, she paid $1,650 in rent each year, for 19800/12=1650

m∠a is 90°

m∠b is 40°