In this case, we'll have to carry out several steps to find the solution. 
Step 01:
Data
Right triangular pyramid 
base = 5 meters 
altitude = 4 meters
Volume = ? 
Step 02:
The volume of a right triangular pyramid
V = 1/3 B * h 
B = 1/2 b * h 


 The answer is:
The volume of the pyramid is 13.33 m³.