1. Find x if the exterior angles of a hexagon are x, x-20°, x+30°, 56°, 39° and 2x.
2.In a regular n-sided polygon, the size of an interior angle is nine times that of an exterior angle. Find the value of n.
form2 maths (angles in triangles and polygons)
2008-02-02 2:23 am
回答 (2)
2008-02-02 2:53 am
1. hexagon has six sides
so the sum of interior angles = (6-2) x 180°= 720°
x + x- 20°+ x +30°+56°+39°+2x = 720°
5x = 615°
x = 123°
2. exterior angle = 360°/n
interior angle of a regular polygon = (n-2) x 180°/n
9x 360°/n = (n-2) x 180°/n
n = 16
2008-02-01 18:55:29 補充：
sorry... 第一題睇錯咗應該係x + x- 20°+ x +30°+56°+39°+2x =360°5x = 255°x = 51°
2008-02-01 18:58:26 補充：
哎呀第二題又計錯應該係exterior angle = 360°/ninterior angle of a regular polygon = (n-2) x 180°/n9x 360°/n = (n-2) x 180°/nn = 20
so the sum of interior angles = (6-2) x 180°= 720°
x + x- 20°+ x +30°+56°+39°+2x = 720°
5x = 615°
x = 123°
2. exterior angle = 360°/n
interior angle of a regular polygon = (n-2) x 180°/n
9x 360°/n = (n-2) x 180°/n
n = 16
2008-02-01 18:55:29 補充：
sorry... 第一題睇錯咗應該係x + x- 20°+ x +30°+56°+39°+2x =360°5x = 255°x = 51°
2008-02-01 18:58:26 補充：
哎呀第二題又計錯應該係exterior angle = 360°/ninterior angle of a regular polygon = (n-2) x 180°/n9x 360°/n = (n-2) x 180°/nn = 20
2008-02-02 2:30 am
1.x + x-20° + x+30° + 56° + 39° + 2x=360
5x=255
x=51
2.5g~wor1sor!
5x=255
x=51
2.5g~wor1sor!
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