What is the area of a circle whose diameter is 10?

Icould really use some with this question.

What is the value of p in the equation y^ = -4x?

Melissa is purchasing a $160,000 home and her bank is offering her a 30-year mortgage at a 4.9% interest rate. in order to lower her monthly payment, melissa will make a 20% down payment and will purchase 3 points. what will her monthly mortgage payment be? a. $645.98 b. $650.46 c. $662.93 d. $606.69