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Graphing Slope-Intercept

Learning Resource Type

Classroom Resource

Subject Area



9, 10, 11, 12


In this PhET activity, students explore the slope-intercept form of a line and connect the slope and y-intercept to the equation of the line. The learning goals for this activity will be to graph a line given an equation in slope-intercept form, write an equation in slope-intercept form given a graphed line, predict how changing the values in a linear equation will affect the graphed line, and predict how changing the graphed line will affect the equation. This activity can be used to help teach a lesson on graphing linear equations. This PheET activity can be downloaded and assigned to Google Classroom.

Mathematics (2019) Grade(s): 09-12 - Geometry with Data Analysis


Evaluate possible solutions to real-life problems by developing linear models of contextual situations and using them to predict unknown values.



  • Quantitative variables
  • Scatter plot
  • Residuals
  • Slope
  • Rate of change
  • Intercepts
  • Constant
  • Ordered pairs
  • Horizontal lines
  • Vertical lines


Students know:
  • Techniques for creating a scatter plot.
  • Techniques for fitting a linear function to a scatter plot.
  • Methods to find the slope and intercept of a linear function.
  • Techniques for fitting various functions (linear, quadratic, exponential) to data.
  • Methods for using residuals to judge the closeness of the fit of the function to the original data.


Students are able to:
  • Accurately create a scatter plot of data.
  • Correctly choose a function to fit the scatter plot.
  • Make reasonable assessments on the fit of the function to the data by examining residuals.
  • Accurately fit a linear function to data when there is evidence of a linear association.
  • Accurately fit linear functions to scatter plots.
  • Correctly find the slope and intercept of linear functions.
  • Justify and explain the relevant connections slope and intercept of the linear function to the data.


Students understand that:
  • Functions are used to create equations representative of ordered pairs of data.
  • Residuals may be examined to analyze how well a function fits the data.
  • When a linear association is suggested, a linear function can be fit to the scatter plot to aid in modeling the relationship.
  • Linear functions are used to model data that have a relationship that closely resembles a linear relationship.
  • The slope and intercept of a linear function may be interpreted as the rate of change and the zero point (starting point).

CR Resource Type

Learning Activity

Resource Provider


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