Interior and exterior angles

Needed the answers as this doesn't have a mark scheme.Thankyou!
1) 12 sides
2) 72 degrees
3) 60 degrees

How can i work out sides when the interior angles are given?

(edited 8 years ago)

Scroll to see replies

Reply 1

Kevin De Bruyne

Original post by z_o_e

Needed the answers as this doesn't have a mark scheme.Thankyou!
1) 12 sides
2) 72 degrees
3) 60 degrees

How can i work out sides when the interior angles are given?

What have you tried? :h:

What do you think you should do?

Reply 2

z_o_e

Original post by SeanFM

What have you tried? :h:

What do you think you should do?

to find the interior angle you need the formulae (n-2) * 180?

Posted from TSR Mobile

(edited 8 years ago)

Reply 3

Kevin De Bruyne

Original post by z_o_e

Needed the answers as this doesn't have a mark scheme.Thankyou!
1) 12 sides
2) 72 degrees
3) 60 degrees

How can i work out sides when the interior angles are given?

If you're referring to the exterior angles as the sides, then what does an interior and exterior angle add up to?

12 is right, I'm brushing up on my angles for the other two questions though. Someone else may know.

Reply 4

Kevin De Bruyne

Original post by z_o_e

Needed the answers as this doesn't have a mark scheme.Thankyou!
1) 12 sides
2) 72 degrees
3) 60 degrees

How can i work out sides when the interior angles are given?

2) the intererior angles of that are indeed 72, but it's asking for the exterior.

3) Yes, it is 60.

Reply 5

z_o_e

Original post by SeanFM

2) the intererior angles of that are indeed 72, but it's asking for the exterior.

3) Yes, it is 60.

Exterior is 108.

Posted from TSR Mobile

Reply 6

Kevin De Bruyne

Original post by z_o_e

Exterior is 108.

Posted from TSR Mobile

Well done, all sorted.

So you just need to remember how to find the interior angles and the exterior angles, and have more faith in your answers. :redface:

Reply 7

z_o_e

Original post by SeanFM

Well done, all sorted.

So you just need to remember how to find the interior angles and the exterior angles, and have more faith in your answers. :redface:

Thanks!

Posted from TSR Mobile

Reply 8

z_o_e

Original post by SeanFM

Well done, all sorted.

So you just need to remember how to find the interior angles and the exterior angles, and have more faith in your answers. :redface:

ImageUploadedByStudent Room1454785478.599969.jpg

You know for this what rule do i use :/

Posted from TSR Mobile

Reply 9

Kevin De Bruyne

Original post by z_o_e

You know for this what rule do i use :/

Posted from TSR Mobile

What do you think? :h:

What if gave you the number of sides and asked you to find the interior angle?

So wha do you do here?

Reply 10

z_o_e

Original post by SeanFM

What do you think? :h:

What if gave you the number of sides and asked you to find the interior angle?

So wha do you do here?

Number of sides-2 * 180

360-answer

Posted from TSR Mobile

Reply 11

Kevin De Bruyne

Original post by z_o_e

Number of sides-2 * 180

360-answer

Posted from TSR Mobile

Not quite - you're appliyng two different concepts there.

(n-2)*180 gives you the sum of all the interior angles. 360-answer would then give you a negative value (unless n<5).

This question gives you the value of the interior angle and asks you to find n.

Actually, this part of my post is useless - never mind.

Going down the external angles route, if you have the number of sides, you can find the interior angle by first finding the exterior angle and then...

So the reverse process is..

(edited 8 years ago)

Reply 12

z_o_e