Decagon

Calculate the area and circumference of the regular decagon when its radius of a circle circumscribing is R = 1m

Correct answer:

S =  2.9389 m2
o =  6.1803 m

Step-by-step explanation:

R=1 m n=10  A=360/n=360/10=36   sinA/2=Ra/2  a=2 R sin(A/2)=2 1 sin(36/2)0.618 m  r=R2(a/2)2=12(0.618/2)20.9511 m  S1=2r a=20.9511 0.6180.2939 m2 S=n S1=10 0.2939=2.9389 m2
o=n a=10 0.618=6.1803 m



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