Consider the following graphic.

The grid of dots above is called "dotpaper". We assume each dot is 1 unit from the next dot horizontally (accross) or vertically (up or down). Of course, dots diagonally next to each other are farther appart. The square **A** above is the "unit square", its area is 1. The four triangles **B** form half a unit square, so they have area ^{1}/_{2}.

These are some rectangles. You can find their area by counting the unit squares they contain. So **A** has area 8, **B** has area 9 and **C** has area 3. Alternatively one can measure the base and height and multiply, for example figure **A** has base 4 and height 2, so area = 4*2 = 8. For **B** the base and height are both 3 so the area is 3*3 = 9 while the last rectangle has base 1 and height 3 so its area is 1*3 = 3. In general the formula for the area of a rectangle is *A = bh* where b is the base (horizontal) and h is the height (vertical).

We can use the formula *A = ^{1}/_{2} bh* for a triangle. In triangle

Remember the important thing in dot figures is that we can only use horizontal or vertical distances, never slant distances.

Now you try one.