Open navigation menu
Mathematics
Explore quadrilaterals
Loading resource…
Loading resource…
Drag corner B to change the shape
Drag a corner, a side or the inside of the shape and watch its name and properties change.
Display
Sound and spoken descriptions
Touch the shape or enable sound to start listening.
Keyboard and precision
Tab to a corner or side, then use arrow keys. Hold Shift for smaller steps. Page Up/Down use larger steps; Home resets the selected part, End makes a safe example. Alt+Shift+R resets the shape; Alt+C reads its properties.
- Equal sides
- AB = BC = CD = DAAB = BC = CD = DA
- Equal angles
- angle A = angle B = angle C = angle DA=B=C=D
- Parallel sides
- AB is parallel to CDABCDBC is parallel to DABCDA
- Right angles
- angle A, angle B, angle C, angle DA,B,C,D= 90°
Also a: Convex quadrilateral, Trapezoid, Isosceles trapezoid, Kite, Parallelogram, Rectangle, Rhombus
Side and angle measurements
- Area
- 36 u²
- Perimeter
- 24 u
- Angle sum
- 360°A+B+C+D= 360°
| Corner | Angle | Side | Length |
|---|---|---|---|
| A | 90° | AB | 6 u |
| B | 90° | BC | 6 u |
| C | 90° | CD | 6 u |
| D | 90° | DA | 6 u |
Reading the properties
Four equal sides and four right angles
The same colour and the same number of ticks or arcs mean equal.
A shape can belong to several families. The name above is the most specific name for its current properties.
A small tolerance helps you find named shapes by dragging; measurements show actual values.
Model notes
- The shape has four ordered corners A–B–C–D. Sides cannot cross; both convex and concave shapes are included.
- Shape families are inclusive: a square is also a rectangle, a rhombus and a parallelogram. A trapezoid has at least one pair of parallel opposite sides here.
- Shape names use small tolerances so named shapes are easier to find by dragging. Approximate classification is not an exact geometric proof.
- Equal sides share a colour and a number of ticks; equal angles share a colour and a number of arcs. Cross marks on a side are length units; angle wedges divide angles into 30° units. Triangle? keeps four corners with one angle close to 180°.
- Unique sounds identify specific shapes; layered sounds represent shape families. All properties remain available when sound is muted.