Keep the useful ideas close.
Sixteen connected concepts, worked examples, and guided paths through the tools.
Start with geometry
Build from lengths to shapes.
Make sense of trigonometry
Connect a turning point to a wave.
Explore the coordinate plane
Describe position, distance, and movement.
Every concept, in one place
The Pythagorean theorem
The relationship that holds every right triangle together.
The law of cosines
Pythagoras, extended to every triangle.
The law of sines
A shared ratio between sides and their opposite angles.
Heron’s formula
Find a triangle’s area using only its three sides.
Radians & degrees
Two ways to describe the very same turn.
Sine, cosine & tangent
Three ratios. One right triangle.
Area & perimeter
The space inside is different from the distance around.
Volume & surface area
What fits inside, and what covers the outside.
Polygon angles & diagonals
A triangle-based explanation for many-sided shapes.
Distance & midpoint
Pythagoras meets the coordinate plane.
Slope & line equations
Describe a direction, then locate the line.
Arc length & sector area
Measure a slice of a circle.
Transforming sine & cosine graphs
Four parameters shape an entire wave.
Translations, rotations & reflections
Move a shape while keeping track of every vertex.
Similarity & scale factors
Why doubling the size changes more than you might expect.
Triangle medians & the centroid
Find the balance point of a triangle.