Question

(2,-9)(3,2) and (3,-9) find the area of the triangle

Answer 1

Several ways:

1. Heron's Formula,
google it and apply

2.
- find the equation of one of the sides and write it in the form Ax + By + C = 0.
- find the length of the line used to find the equation.
- Use the method of finding the distance from a point to a line.
- You now have the base and the height of the triangle, easy from here.

3. Easiest way is to use the following algorithm
--- list the points in a column, repeat the first one you listed

2 -9
3 2
3 -9
2 -9

area = (1/2)|sum of downproducts - sum of uproducts|
= (1/2)|4 - 27- 27 -(-27 + 6 - 18)|
= (1/2)|-11|
= 11/2
= 5.5

Answer 2

Try plotting the points.

Note that (3,2) and (3,-9) form a vertical line of length 11

The point (2,-9) is one unit away, so you have a triangle with base 11 and height 1.

Now, is that so hard?