Write each percent as a decimal . 72%

Divide to undo the multiplication of n times 72. Move the decimal point two places to the right to write the decimal as a percent. You can estimate to see if the answer is reasonable. Use 10% and 20%, numbers close to 12.5%, to see if they get you close to the answer.
Hope this helps

Percent to Decimal:
72% = 0.72

The correct answer would be shape of function b = 2× slope of function a.