Question

A regular polygon has possible angles or rotational summetry of 20, 40, and 80 degrees. How many side does the polygon have?

Answer 1

The number of sides regular polygon have = 18

Explanation:

The possible angle or rotational symmetry is 20° , 40° , 80° of any regular polygon .

now,

Symmetrical under 20° Rotation is also symmetrical on rotation of any multiple of 20°

So, number of sides = n =
`(360)/(External angle)`

I.e n =
`(360)/(20)`

So, n = 18

Hence the number of sides the polygon have 18 Answer