# Math Help - Circumference of the Base Circle of an Open Cylinder...

1. ## Circumference of the Base Circle of an Open Cylinder...

The page that this assignment is printed on is to be folded to form an open cylinder with a 1 cm overlap.

1. Measure the length and width of this page to the nearest millimetre. What will be the circumference of the base circle of the open cylinder? Use this measurement to find the radius of the base circle of the open cylinder.

(I measured this - Length: 296 mm; Width = 210 mm). I am aware this this question may seem overly simple to you, but I cannot seem to understand what I have to do. I keep calculating the incorrect answer. Any help, if you can do so, is appreciated. Thank you in advance!

2. I would have guessed that the circumference would be 286 mm (296 mm with a 1 cm overlap). From there, you would use the formula for the circumference of a circle
$C = 2\pi r$

to find the radius of the base of this open cylinder:
\begin{aligned}
C &= 2\pi r \\
286 &= 2\pi r \\
r &\approx 45.52\,mm \: \text{or} \: 4.552\,cm
\end{aligned}