Thread: Co-ordinate Geometry: Colinear points

A, B and C are three colinear points. A and B are respectively (3,4) and (7,7) and AC is equal to 10 units. Find the coordinates of C.

Originally Posted by Ilsa

A, B and C are three colinear points. A and B are respectively (3,4) and (7,7) and AC is equal to 10 units. Find the coordinates of C.

Let h,k)" alt="Ch,k)" />. From the given we know:
and .

Solve for .

could u pls explain which formula u have used?

Originally Posted by Ilsa

could u pls explain which formula u have used?

Slope: collinear points determine the same slope.
Distance.

Hello, Ilsa!

Did you make a sketch?

are three collinear points.
and are (3,4) and (7,7), respectively,
and is equal to 10 units.
Find the coordinates of

Code:

      |                                      C
      |                                      o
      |                                  *   :
      |                              *       :3
      |                      B   *           :
      |                 (7,7)o - - - - - - - +
      |                  *   :       4
      |              *       :3 
      |      A   *           :
      | (3,4)o - - - - - - - +
      |             4
      |
      |
    - + - - - - - - - - - - - - - - - - - - - - -
      |

To go from point to point , we move: right 4, up 3.

The length of is: .


Since the length of is 10, then: .

To go from point to point , we move (again): right 4, up 3.


Therefore, point C is at: .

pls sir i wud be grateful of u if u pls help me doing the sum in intermediate level or ordinary level or according to the ratio theorem or distance formula