 We're going to redo the third example from the previous page: "Find the distance between the points (-3, 3) and (3, -5)" or "Find the length of the line segment joining (-3, 3) and (3, -5)" Here's the formula:  Δx and Δy are the same side lengths as before, but we don't need a diagram! Fill the numbers into the formula: (-3, 3) and (3, -5)  Notice that we subtract right to left. That's what most people do.   You can get the answer even faster if you can take step 2: and enter it directly into your Ti84 calculator to get the answer 10.  Be careful to differentiate between 'subtract' (-) and 'negative' (-). On the calculator 'negative' is smaller. Let's try a second example. This time we'll just do it without any explanations, so you can see how quick the method is when you don't need to draw a diagram. "Find the distance between (-2, 6) and (4, 10)"  or if you do the calculation on your calculator, it's just three steps: 
Move on to page four and try a few yourself. You'll need a pencil and paper and a calculator. |