Math · AreaVISUAL DISCOVERY 02 OF 1,100
Two Triangles Make a Parallelogram
Starter · about 6 minutes · a little curiosity goes a long way
For grown-ups
Today’s little discovery
A copy of any triangle can rotate beside it. Together they make a parallelogram with the same base and perpendicular height, so one triangle has area base × height ÷ 2.
Point to the perpendicular height; it is not always a sloping side.
This is a learning model. Try the take-home activity together.Voice settings
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Your selected voice and opening narration get ready when the page opens with Sound on. The first visit downloads a voice model (about 92 MB), which your browser can cache. No lesson text is sent to a speech service.The sample plays once and does not change the Sound on/off setting.- Wonder
- Guess
- Try it
- Discover
- Celebrate
HERE’S A LITTLE WONDER…
Why is a triangle half of base times height?
A triangular garden tile has a matching twin that can turn and fill the missing corner.
No rush. Try an idea and see.