Ahmed found the volume of a cone having both a height and a diameter of 6 centimeters. His work is shown below.

What was Ahmed’s first error?
In Step 1, the radius should be found by multiplying the diameter by 2.
In Step 2, the formula 2pi r should be used to find the area of the circle.
In Step 3, the resulting area should be in terms of pi
In Step 4, the units of the resulting volume should be cm^2