Find the slope of a line
Work out rise over run between two points, such as (2, 1) and (6, 4).
Slope tells you how steep a line is: m = (y2 − y1) / (x2 − x1). For (2, 1) and (6, 4), m = (4 − 1) / (6 − 2) = 3/4.
Classic Graphing 84
Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.
Type (4 − 1) ÷ (6 − 2). Brackets keep each subtraction together.
(4−1)÷(6−2)For a fraction instead of a decimal, choose ►Frac from MATH (item 1) and press enter.
math1enter
You should see(4−1)/(6−2)►Frac 3/4
Natural Scientific 991
Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.
Type (4 − 1) ÷ (6 − 2) and press =. The answer is shown as a fraction.
(4−1)÷(6−2)=
You should see(4−1)÷(6−2) 3/4
Classic CAS
Start on the main screen: Press home to open the Home menu (Calculator, Graphs, Settings, and more). Choose Calculator, or press esc to go back to the calculation page.
Type (4 − 1) ÷ (6 − 2) and press enter.
(4−1)÷(6−2)enter
You should see(4−1)/(6−2) 3/4
RPN Scientific 15
Start on the main screen: There is no menu to leave. Press the back arrow to clear a number you are typing, or CLx (g then back arrow) to clear the X register.
Work out the rise: 4 ENTER 1 −. Then the run: 6 ENTER 2 −.
4ENTER1−6ENTER2−Press ÷. The rise is divided by the run.
÷
You should see0.7500
Tips
- Use the same point order on top and bottom. If you subtract (point 2) − (point 1) on top, do the same below.
- A vertical line has run 0, so the calculator reports an error. Its slope is undefined.
Related guides
- Distance between two pointsFind how far apart two points are on a graph, using the distance formula.
- Find the midpoint of a segmentAverage the x values and the y values of two points to find the point halfway between them.
- Graph a functionType an equation such as y = x² − 4 and draw its graph, then check a point on it.