Circle areas

5. 

12, 12 angle of 20. 

To find the other one, law of cosines. 

x^2 = 12^2+12^2 - 2*12*12*cos(20 degrees)

x^2 = 17.3685252137

x = 4.16755626401

Oh no, it looks like we got different answers. :((

=^._.^=

5)         R = 12         ∠θ = 120º    (NOT 20 )

Chord     C = 2[ sqrt(12² - 6²)]

But..., if   ∠θ = 20º  then the answer is "slightly" different:

C = 2[sin(10º) * 12]   ==>      24 sin(10º)