17mm is the answer.
To solve this:
1.) Find the radius of the entire pencil.
The radius of the graphite is .75 (half the diameter) and the thickness of the wood is 2, so 2 plus .75 gives you a total radius of 2.75.
2.) Using this radius, find the circumference of the entire pencil using the equation C = 2 • pi • r.
C = 2 • pi • r
C = 2 • 3.14 • 2.75
C = 17.27 (17 is the answer after rounding to the nearest millimeter)
