Where where is the formula you didn't even post a picture?
Answer:
email or call or talk to your teacher and ask why
Step-by-step explanation:
Answer: 
Step-by-step explanation:
The formula for the lateral area of a cone
is:

Where:
is the radius of the circular base of the cone
As we know its diameter
, its radius is 
is the height of the cone

This is the lateral area of the volcano with the shape of a cone