A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 one year ago
The number of triangles whose vertices are the the vertices of the vertices of an octagon but none of whose sides happen to come from the sides of the octagon.
anonymous
 one year ago
The number of triangles whose vertices are the the vertices of the vertices of an octagon but none of whose sides happen to come from the sides of the octagon.

This Question is Closed

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0@hartnn Can you please help?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.0dw:1444576861098:dw Lets take the vertices of the octagon as A,B,C,D,E,F,G,H

hartnn
 one year ago
Best ResponseYou've already chosen the best response.0the logic is, we can't take adjacent vertices of octagon to be vertices of the triangle. so we can't have A,B,C , but we can have A,C,E

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0How many of such triangles would be there?

hartnn
 one year ago
Best ResponseYou've already chosen the best response.0thats just the first step... Pick 2 vertices. say A and C, (note you can't pick 2 adjacent vertices) try to find how many triangles that can e formed using these 2 vertices

hartnn
 one year ago
Best ResponseYou've already chosen the best response.0here are 2 lists: {A,C,E,G} and {B,D,F,H} we can choose 2 coordinates from the 1st list and the 3rd has to be from the 2nd list. this can be done in \(^4C_2 ~~ ways\)

hartnn
 one year ago
Best ResponseYou've already chosen the best response.0actually \(^4C_2 \times ^4C_1\) ways. because there are 4 different vertices in 2nd list.

hartnn
 one year ago
Best ResponseYou've already chosen the best response.0same is true when you select 2 vertices from 2nd list and 1 from the 1st. so in all, there will be \(\Large 2 (^4C_2 \times ^4C_1)\) ways :)
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.