On a scale model of a room, the scale was 1 cm: 1.5 ft
The length of the model is 20cm
Then the actual length of the room in ft is given by
![\frac{1\operatorname{cm}}{1.5\: ft}=\frac{20\operatorname{cm}}{x\: ft}]()
Where x is the actual length of the room in ft that we want to find out.
Let us solve for x in the above equation
![\begin{gathered} \frac{1\operatorname{cm}}{1.5\: ft}=\frac{20\operatorname{cm}}{x\: ft} \\ x\: ft=\frac{20\operatorname{cm}*1.5\: ft}{1\operatorname{cm}} \\ x=30\: ft \end{gathered}]()
Therefore, the actual length of the room is 30 ft.