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Please helpppppppppppp

Please helpppppppppppp-example-1
User Krash
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1 Answer

2 votes

Answer:

A≈1107.97cm²

Explanation:

Area of one triangle:


A_(T) =(1)/(2) c*c*sin36=(1)/(2)c^(2) sin36

Area of polygon:


A=10*A_(T) =5c^(2) sin36

Cosine formula:


12^(2) =c^(2)+c^(2) -2*c*c*cos36 \\144=2c^(2) -2c^(2)cos36\\2c^(2)(1-cos36)=144 \\c^(2)(1-cos36)=72\\c^(2)= (72)/(1-cos36)

Area of polygon:


A=5c^(2)sin36= 5*(72)/(1-cos36) *sin36=1107.966073

A≈1107.97cm²

Please helpppppppppppp-example-1
User Ncx
by
8.2k points

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