Answer:
In circumference, pi is in the formula to solve circumference. In the formula for area you also need pi but with the square of the radius. The diameter is two times the radius and sometimes you need the diameter to find something of a circle. Pi is in all the formulas of circles including diameter radius and formula of circumference.
Step-by-step explanation:
Hope this helps! I don't really know how to answer the question like idk if there's a specific answer but if this is wrong I'm sorry
