4π5

To convert from slope to percent grade, multiply the slope by a hundred.

4π5=4π5⋅100

Factor 5 out of 100.

4π5⋅5(20)%

Cancel the common factor.

4π5⋅5⋅20%

Rewrite the expression.

4π⋅20%

4π⋅20%

Multiply 20 by 4.

80π%

Convert the Slope to Percent Grade (4pi)/5