Question

Please helpppppppppppp

Answer 1

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