唔明點解計唔到=p

let the exterior angle of the equiangular polygon be x°
the we have
x=(25%)(180-x)
0.75x=45
x=60

so each interior angle is 120°

let the number of side of the polygon be y

(y-2)(180)/y=120
y=6

so the poltgon is hexagon

2007-01-03 17:19:04 補充：
sorry something wrong...........This correctlet the exterior angle of the equiangular polygon be x°the we have x=(25%)(180-x)1.25x=45x=36so each interior angle is 144°let the number of side of the polygon be y(y-2)(180)/y=144y=10so the poltgon is decagon

let x be the interior angle of the polygon
let y be the exterior angle of the polygon

x + y = 180 　　(adj. angles on st. line)
25%x = y

25%x = 180-x
x = 720-4x
x = 144

So the interior angle of that polygon is 144 degree.

let the polygon has k sides
144k = (k-2) x 180 (angles sum of polygon)
144k = 180k - 360
k = 10

So, the polygon has 10 sides and this is a decagon.