Maths question scale drawings and determining area

A plan of a building site uses a scale of 1:150. What field lengths would be represented by the following plan lengths? (answer in meters.)

a) 12 mm b) 4.5cm c) 150 mm d) 2.25 cm

I don't know what to do please help

All you have to do is multiply each value by 150 and you will have the actual length. Don't forget to change the units