Answer:
$9.92 (rounded off to nearest cent)
Step-by-step explanation:
Square of 7-inch radius pizza =
= 49 inches
49 Inches = $6
Square of 9-inch radius pizza =
= 81 inches
Given 49 Inches = $6
1 inch =$ 
I will leave it as a fraction as it is not the final answer, rounding it off will result in a loss of accuracy.
81 Inches = 
= $9.92 (rounded off to nearest cent)
It's A. If an instrument is a piano, then it has keys.