How many triangles may be formed by joining any three of nine points on a plane when five of them are collinear.

How many triangles may be formed by joining any three of nine points on a plane when no three of them are collinear.

How many triangles can be obtained by joining the vertices of a quadrilateral?

How many triangles can be obtained when the vertices of a hexagon are joined?

Find the area of the triangle formed by joining the mid-points of the sides of the triangle whose vertices are (0,-1),(2,1) and (0,3).Find the ratio of this area to the area of the given triangle.

In a plane 10 straight lines are such that no two of these are parallel and no there of them are concerned.How many triangles can be formed by these lines?

Show that the triangle formed by the three points (5,-2),(6,4) and (7,-2) is isosceles.

Two women and five men together can finish a work in 4 days. But three women and six men can finish the same work in three days. Determine the time taken to comlete the work by a woman and by a man when each of them works alone.

Find how many words can be formed of the letters of the words: DAUGHTER so that the vowels may never seperated.

Fill in the blank If three points are collinear,the area of the triangle form is_______.