Let n be the number of sides of each polygon.
For angles...
Size of each angle = \(\frac{(n-2)(180)}{n}\)(in degrees)
For perimeters and areas(i love area questions :D)
Let n be the number of sides of each regular polygon and x be the length of each side
Perimeter = nx
Also I invented some of the area formulas to get the area of regular polygons(Length of each side = x)
(all trig functions in degrees)
Regular pentagon: \((x^2sin72)(1+cos36)\)
Remarks: The original regular pentagon area formula needs to know the apothem but my formula need not.
Regular hexagon: \(3\sqrt{3}x^2\times\frac{1}{2}\)
Regular octagon: \((2x^2)(1+\sqrt2)\)
I found this all in one day. I used trigonometric functions when finding the regular pentagon and hexagon area formula and pythagoras theorem when finding the regular octagon area formula. Hope this can help you :D