Common Core Math - Grade 8
Lesson Plan
Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line
Goals / Objectives
Construct slope triangles between two distinct points on a non-vertical line and explain how these triangles relate to the calculation of slope
Use the properties of similar triangles to prove that the slope between any two distinct points on a non-vertical line is always the same
Derive the equation y = mx for a line that passes through the origin, starting from the definition of slope and the similar triangles argument
Derive the equation y = mx + b for a line that intercepts the vertical axis at the point (0, b)
Connect the parameters m and b in the equation y = mx + b to their geometric meanings: m as the constant rate of change (slope) and b as the y-intercept
Standards
8.EE.B.6
8.EE.B.6: Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation y = mx for a line through the origin and the equation y = mx + b for a line intercepting the vertical axis at b.
Academic Vocabulary
Not in our source material
Materials
Remediation
Enrichment
Accommodations
Not in our source material
Anticipatory Set / Bell Work
Modeling
Check for Understanding
This lesson’s brief has no Formative Assessment or Assessment Ideas