Answer:
45 km per hour
Explanation:
We want to find the tricycle's speed in kilometers per hour. 
Therefore, we must divide the kilometers traveled by the number of hours. 
speed= kilometers / hours 
The tricycle travels 180 kilometers in 4 hours. 
speed= 180 km / 4 hrs 
Divide 180 km by 4 hrs.
⇒ 180/4=45 
speed= 45 km / hour 
The tricycle's speed is 45 kilometers per hour.