Math/Trig
posted by CJ .
Find the radius of a circle with a central angle of pi/7 and a length of the intercepted arc equal to 7.7 cm. Round your answer to the nearest tenth.

angle*radius=arc
radius=7.7cm/(PI/7)=7.7*7cm/PI
check that. 
I do want to point out that math teachers don't understand units and place value. "Round your answer to the nearest tenth"...what? cm, meter.
For instance, if you do that math...
answer: 17.1569029cm or 17.2cm or
0.171569029m or .2 m
Physics and chemistry teacher would agree, the problem should have stated
a) Round your answer to the nearest tenth cm, or
b) Round your answer to the nearest tenth meter, or
c) round your answer to two (or desired) significant digits.
Because the arc was measured to two significant digits (7.7cm), the answer could be nor more than two, or 17cm. 
it says to find the radius