Answer
11.7 inches (rounded)
Work Step by Step
We’re changing from a metric length unit to a U.S. length unit. In the “Metric to U.S. Units” side of the table, you see that 1 centimeter = 0.39 inch. Two unit fractions can be written using that information.(1 cm)/(0.39 inch) Or(0.39 inch)/(1 cm).
Multiply by the unit fraction that allows you to divide out centimeters (that is, centimeters is in the denominator).
30 cm * (0.39 inch)/(1 cm) = 11.7 inches(rounded)