To find the actual length of the room, we'll use the scale of 1:40 given in the plan.
If 1 cm on the plan represents 40 cm in reality, then 16 cm on the plan represents:
16 cm × 40 = 640 cm
Converting 640 cm to meters:
640 cm ÷ 100 = 6.4 m
So, the correct answer is:
4. 6.4 m