If the radius of a circle is 4 cm what is the circumference

To start, since you know the radius of a circle is half of the diameter, and the formula for the circumference of a circle is C=Dπ (d is diameter) or C=2πr, you would first find the diameter of the circle which is 8 (you find this by multiplying the radius by 2). Then, if you multiply the diameter by π or if you want to round, use 3.14. This would result in 8π or 25.12 cm as your circumference. (hope this helps XD)

The peak above is part of the  sierra madre occidentals ,  a chain of volcanic mountains that runs through the middle of central america.