Answer:
360
Explanation:
You have degrees, so just plug stuff in and cross multiply. This gives you 20π=180*(x radians). (x is what we're solving for.) Solving gives x= π/9 radians.
Now we know θ in terms of radians. We can just plug our numbers in and solve!
40=r(π/9)
Divide by π/9 to get r=360/π cm!