JM29 · Lesson 29
Quadrilaterals
Classify the family, or open Mid-pt & intercept to prove those theorems with similar triangles.
Lab 1 · Shape detector & prove
Drag any corner — what shape is it?
Pick a preset, or drag A–D. // marks use arrowheads; equal lengths use tick groups (same tick count = same length only). Marks are offset so they do not stack.
How to prove this shape
If more than one reason works, pick a button. Follow the steps.
Comparison table
✓ = must be true for that shape. The row for your current detection is highlighted.
Lab 2 · Mid-pt. thm. & Intercept thm.
Parallel lines playground
Drag near the left end of a green line to move it. Drag blue/purple end-handles to tilt. Mid-pt: match PB = BC and PE = EF. Intercept: match AB = BC (then DE = EF follows).
Lab 3 · Reason bank
Pick a reason — see it on a figure
Tap a reason code. The frame shows a matching diagram and the wording you write in a proof.
Pick a reason card to see an explanation with a figure.
Game 1 · Identifying quadrilaterals
The Search for the True Princesses
Click the scene (or press Space) to move the story on.
Game 2 · Mid-point theorem vs intercept theorem
Which theorem?
Solitaire: three aces, two columns, draw pile at the top right.
Read the six-page English story in order.
Summary
Coming soon.
Quiz
Coming soon.