Ask your own question, for FREE!
Mathematics 42 Online
OpenStudy (anonymous):

I need to find the perimeter of an Annulus. The radius of the large circle is 2, small circle is 1. The area of the annulus is 9.4 square units. Anyone know how to find out the perimeter? :(

OpenStudy (anonymous):

An annulus is simply a ring - you need to add the circumference of the outside circle and the inside circle (the "hole" in the middle of the ring.) \[Total C=2\pi{r_1}+2\pi{r_2}\] \[=2\pi{({r_1+r_2})}\] <-- \[{r_1}\] is the outer radius. Plug and chug.

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Latest Questions
ilovealotofpeople: can someone tlk to me on discord
1 hour ago 0 Replies 0 Medals
rose12345: helppppp
1 hour ago 1 Reply 0 Medals
ilovealotofpeople: who got discord
2 hours ago 1 Reply 0 Medals
ThePhenom19: Why is my dog Dumb
4 hours ago 0 Replies 0 Medals
81828: help me ?
7 hours ago 16 Replies 0 Medals
81828: can yall help ???
8 hours ago 9 Replies 1 Medal
81828: jks
8 hours ago 0 Replies 0 Medals
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!