Posted by **please help** on Monday, January 14, 2013 at 8:18pm.

distint points a, b, c, d, e, and f are marked on a circle. How many triangles can be formed using these points as vertices?

- geometry -
**Allyson**, Monday, January 14, 2013 at 8:20pm
Draw a circle, form as many triangles as you can, and count.

- geometry -
**please help**, Monday, January 14, 2013 at 8:23pm
ok i tried that that its hard why dont u try and tellme the answer ?

- geometry -
**Reiny**, Monday, January 14, 2013 at 8:35pm
You have 6 points on a circle.

It is not possible to have 3 of them forming a straight line (not a triangle) so the question becomes how many choices are there of 3 elements form 6

or C(6,3) = 6!/(3!3!) = 20

## Answer This Question

## Related Questions

- math - There are nine points on a piece of paper. No three of the points are ...
- Math: Combinations - There are 20 points all in one straight line and 15 others ...
- Geometry - Which one of these is NOT a step used when constructing an inscribed ...
- math- algebra- help please! - 12 points lie on a circumference of a circle how ...
- analytic geometry/graphing problem - The vertices of a triangle are the points ...
- 7th Grade Geometry - A Rectangle with vertices A B C AND D. The triangle is ...
- math - the number of noncollinear points needed to determine a circle Two. The ...
- Geometry - Let A be a convex 61− gon. We then place n points {x i} n i=1 ...
- math - suppose n points are in space, no three are collinear and no four or are ...
- Math Geometry - A cube has 8 vertices. For each pair of distinct vertices, we ...

More Related Questions