Circumscribed 22713

Calculate the circumference and the area of a regular ten-angle polygon if the radius of the circumscribed circle r = 20 cm.

Correct answer:

S =  1175.5705 cm2
o =  123.6068 cm

Step-by-step explanation:

R=20 cm n=10  A=360/n=360/10=36   sin A/2 =  Ra/2  a=2 R sin(A/2)=2 20 sin(36/2)12.3607 cm  r=R2(a/2)2=202(12.3607/2)219.0211 cm  S1=2r a=219.0211 12.3607117.5571 cm2 S=n S1=10 117.5571=1175.5705 cm2
o=n a=10 12.3607=123.6068 cm

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