Answer:
1:30
Explanation:
A building is 10cm tall.
Actual building is 3m tall.
1m = 100cm
3m = How many cm?
Cross multiplying gives:
3 × 100 = 300cm
The scale used here is:
10 cm represents 300cm
or
10:300
Simplifying gives a scale;
1:30
Meaning that 1cm represents 30cm of the actual building.