Find the lengthof a side the perimeter of a regular nine-sided polygon with radius 5 uniys
360/9 = 40 degrees
9 isoceles triangles with two sides length 5 and angle between = 40
what is the third side?
other angles are 2 A +40 = 180 so A = 70 degrees
law of sines
sin 70 / 5 = sin 40/side
side = 5 sin 40 / sin 70