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Topic review (newest first)
- MathsIsFun
- 2005-10-15 08:57:05
A septagon has 7 sides. If it is irregular, then it could have any variation of side lengths and angles.
- Math Student
- 2005-10-15 03:13:10
Thanks for that.
Ermm... do you know how to draw the irregular septagon? I'm still having trouble with it.
Sorry about number 2. It's sometimes hard to show fractions
- mathsyperson
- 2005-10-15 03:06:08
1) Yes, you're right. Sorry.
2) I took 4 (1/2) to mean a strange way of saying 2, so you're right there as well. Sorry again.
- Math Student
- 2005-10-15 03:02:58
There was a mistake with your number 1. 900/8 is 112.5 not 125. I got 112.5 but I can't draw the shape.
For number 2 I got 20?
The bottom two angles are:
4 1/2x +4 1/2x
9x/2 + 9x/2 = 18x/2 = 9x
9x+x = 10x
180° /10=18°
therefore
x=18°
360/18=20
- mathsyperson
- 2005-10-15 02:45:39
1) A heptagon has (7-2)*180 = 900 degrees totalling its internal angles.
All of the internal angles in this heptagon total 8x. Therefore, x = 900/8 = 125°
2) I won't bother explaining because you've done it and the explanation is lengthy, but I got it to be a hexagon. Am I right?
3) The external angles of a polygon always add to 360°. The average external angle is (8+12)/2 = 10°, so there are 360/10 = 36 sides.
- Math Student
- 2005-10-15 02:38:43
Don't nother wiht munber 2! I've worked that one out.
Oh yes, for number 1 could you draw the shape out for me? I found out that the angle should be 112.5° but I'm not sure if that is right.
- Math Student
- 2005-10-15 01:00:29
1)
A heptagon has 6 equal angles x and one angle 2x. Find the value of x.
2)
PQ is one side of a regualar polygon with centre O.
If y=4 (1/2)x find the number of sides in the polygon.
3)
Half of the exterior angles of a polygon are 8° and the other exterior angles are each 12° . How many sides has the polygon?