Original: 13.7

New: 40.2

Since the new amount is greater than the original, this is a percent of increase.

The amount of change = New Amount – Original Amount.

 The amount of change = .

Let r be the percentage of increase.

Use the original number, 13.7 as the base.

The percent proportion is

To solve for r, first find the cross products.

                              (Multiply: )

                         (Divide each side by 13.7)

                                        (Cancel common terms)

                                       (Divide: )

The percentage of increase by 193.43%

The percent of change is a percent of increase.

The percentage of increase by 193.43%.