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Geometry

Quadrilateral explorer

Drag corners. Watch the math. Drag any of the four vertices and watch sides, angles, diagonals, perimeter, and area update in real time. The tool names the shape as you go: square, rectangle, rhombus, parallelogram, trapezoid or kite.

geometry · parallelogram
270152270152ABCD

Classification

Parallelogram

Both pairs of opposite sides parallel and equal.

  • Sides270, 152, 270, 152
  • Angles118°, 62°, 118°, 62°
  • Perimeter844 u
  • Area37 800 u²
Geometry tool, as it looks on the board

Who can use it

Without an account, with a free one, and on Plus.

  • Without an account

    Open the page and use it.

    • Nothing yet. A free account opens it.

  • Free account

    Sign in is free, with no payment and no card.

    • The whole tool

  • Plus

    The paid plan. Every new account starts with 30 days of it free.

    • Included

Features

What it does.

  • Drag any vertex

    All four corners are grab handles. Stretch, skew, mirror, the shape responds smoothly so the class can see how a property changes the moment a side moves.

  • Live measurements

    Side lengths, interior angles, both diagonals, perimeter, and area are computed every frame. The angles always sum to 360°, just like the textbook says.

  • Auto-classification

    The tool calls out exactly what kind of quadrilateral you've drawn, square, rectangle, rhombus, parallelogram, trapezoid, kite, and explains why.

Use cases

In the classroom.

Geometry: from parallelogram to rhombus
Start from the parallelogram preset. Drag a vertex until all sides equal, watch the classification flip to 'rhombus' as the kids predict it.
Properties of a square
Square preset on screen. Drag one corner so it's no longer a right angle. Ask: what's it now? Reverse to recover.
Area exploration
Hold base and height of a rectangle constant, then slant the top. Class watches the area stay the same, a clean introduction to base × height.
Diagonals as a shape clue
Show the diagonals on. Build a kite, a rhombus, a rectangle. Discuss which diagonals are equal, perpendicular, or bisecting.

Try it with your class.

A teacher account opens quadrilateral explorer and the rest of the tools. Every new account starts with 30 days of Plus free, with no card.

Start for freeOpen the explorer