# What is the area of a triangle with the vertices at (-1,-1) , (3,-1) . and (2,2)?

Feb 9, 2016

Use:
$\left(\textrm{A r e a o f \triangle}\right) = \frac{\left(h e i g h t\right) \left(b a s e\right)}{2}$
Plot the coordinates out on a piece of graph paper. It can then be seen that height=3 and base=4, therefore the area is 6.

#### Explanation:

Use:
$\left(\textrm{A r e a o f \triangle}\right) = \frac{\left(h e i g h t\right) \left(b a s e\right)}{2}$
Plot the coordinates out on a piece of graph paper. It can then be seen that height=3 and base=4, therefore the area is 6.

You don't even need to plot them out as the height is the difference in the y coordinates:
height = 2 - (-1) = 3.

The length of the base is the difference in the x coordinates of the two lower vertices, (-1,-1) and (3,-1):
base = 3 - (-1) = 4

Thus:
Area = $\frac{\left(3\right) \left(4\right)}{2} = \frac{12}{2} = 6$