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Maths year 11

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Reply 400
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z_o_e
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Original post by z_o_e
What about this?

Do I find the interior angle and subtract that one by 180?



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Angles BCD and CDE are just the exterior angles of the pentagon. The triangle CDF is isosceles.
The formula for exterior angles is 360/n, where n is the number of sides.
Reply 402
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z_o_e
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11
Original post by B_9710
Angles BCD and CDE are just the exterior angles of the pentagon. The triangle CDF is isosceles.
The formula for exterior angles is 360/n, where n is the number of sides.


I got 72 degrees

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Original post by z_o_e
I got 72 degrees

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I get 36 degrees for the angle asked for in the question.
Reply 404
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z_o_e
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11
Original post by B_9710
I get 36 degrees for the angle asked for in the question.


How did you work it out?

36*3= 108 not 180
Original post by z_o_e
How did you work it out?

36*3= 108 not 180


Triangle is not equilateral, it is an isosceles triangle.
Reply 406
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z_o_e
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11
Original post by B_9710
Triangle is not equilateral, it is an isosceles triangle.


How did you work it out?
Angles CDE and BCD are both 72 degrees (exterior angles of the pentagon = 360/5), then
180-2(72) = 36 degrees.
Reply 408
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z_o_e
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Original post by B_9710
Angles CDE and BCD are both 72 degrees (exterior angles of the pentagon = 360/5), then
180-2(72) = 36 degrees.


Got it xx



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Reply 409
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z_o_e
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Original post by B_9710
Angles CDE and BCD are both 72 degrees (exterior angles of the pentagon = 360/5), then
180-2(72) = 36 degrees.


Wb this



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Original post by z_o_e


The triangle is isosceles, angles EBF and BEF are equal. This allows you to work out angle BFG and then x (co interior angles).
Reply 411
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z_o_e
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11
Original post by B_9710
The triangle is isosceles, angles EBF and BEF are equal. This allows you to work out angle BFG and then x (co interior angles).


How's this?


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Original post by z_o_e


Angles in a triangle add to 150 degrees?
Reply 413
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z_o_e
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Original post by B_9710
Angles in a triangle add to 150 degrees?


Isn't it isosceles? So It doesn't have to be equal?
Also BEF is 50

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(edited 7 years ago)
Original post by z_o_e
Isn't it isosceles? So It doesn't have to be equal?
Also BEF is 50

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The triangle being isosceles means that angles BEF and EBF are equal, it does not mean that BFE is 50 degrees though, as angles in any triangle sum to 180 degrees so it wouldn't be possible for BFE to be 50 degrees.
Reply 415
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z_o_e
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11
Original post by B_9710
The triangle being isosceles means that angles BEF and EBF are equal, it does not mean that BFE is 50 degrees though, as angles in any triangle sum to 180 degrees so it wouldn't be possible for BFE to be 50 degrees.




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Reply 416
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z_o_e
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Original post by 34908seikj


Heyaa xx
can you please check this xxx



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Original post by z_o_e
Heyaa xx
can you please check this xxx



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You saying angle BFE is 50 degrees but it is not, angle BEF is 50 degrees, you're getting the properties of the sides and angles in an isosceles triangle mixed up a little I think.
Original post by z_o_e
Heyaa xx
can you please check this xxx



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Hey, I know you didn't ask me, but I just saw this question so I tought I'd help. :smile:

The answer is 80, not 50. You've figured out the fact that two base angles in an isoceles triangle are equal, but the one's you think are the same, actually aren't. Angle FEB and EBF are the same. Angle EFB isn't 50 degrees because the BASE angles are the same, in this case the base is EB.

So if you know that Angle FEB and BEF are 50, then Angle BFE would equal 80, because 180-(50+50)=80.

Angle x is alternate to Angle EFB therefore it must also be 80 degrees. :smile:
Reply 419
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Kaykayv
(2p)^-4 = -16p as it -2x-2x-2x-2 = -16 and then just add the p .

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