How to convert 5 1/4 into a decimal

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.

You receive 15% of the profit from a car wash how much money do you receive from a profit of 300

Is the power produced directly proportional to the wind speed, give reasons for your answer?