Mathalicious: Domino Effect
Mathalicious

In this lesson, students use slope, y-intercept, and linear equations to explore the costs of different-sized pizzas at Domino’s and debate whether the pizza chain should be more transparent in its pricing.

youcubed: Square Mania (9-12)
youcubed (Stanford University)

In this activity students look into a pattern and diagram where their first task is to verify the number of lines and squares.

Real World Math: Exploratory Lessons - Line Patterns
Real World Math

Students will use the Google Earth path tool to connect markings in a geometric pattern of their design. 

NRICH: Diamond Collector
NRICH (University of Cambridge)

Try to collect as many diamonds as you can!

NRICH: At Right Angles
NRICH (University of Cambridge)

Can you decide whether two lines are perpendicular or not? Can you do this without drawing them?

NRICH: How Steep Is the Slope?
NRICH (University of Cambridge)

On the grid provided, we can draw lines with different gradients. How many different gradients can you find? Can you arrange them in order of steepness?

NRICH: At Right Angles
NRICH (University of Cambridge)

Can you decide whether two lines are perpendicular or not? Can you do this without drawing them?Can you decide whether two lines are perpendicular or not? Can you do this without drawing them?

GeoGebra: Parallel Lines in the Coordinate Plane - Quick Exploration
GeoGebra

From what you’ve observed, what can we conclude about any two (non-vertical) lines drawn in the coordinate plane?

GeoGebra: Perpendicular Lines in the Coordinate Plane - Quick Exploration
GeoGebra

What does it mean for lines to be perpendicular (by definition)?

GeoGebra: Meet Slope - IM 8.2.10
GeoGebra

“Meet Slope” from IM Grade 8 by Open Up Resources and Illustrative Mathematics.

GeoGebra: Writing Equations for Lines - IM 8.2.11
GeoGebra

“Writing Equations for Lines” from IM Grade 8 by Open Up Resources and Illustrative Mathematics.

GeoGebra: Using Equations for Lines - IM 8.2.12
GeoGebra

“Using Equations for Lines” from IM Grade 8 by Open Up Resources and Illustrative Mathematics.