Gallery
Discover apps people built on Collabby by chatting. Run them, then remix to make them yours.
Inscribed Angles and Tangents
Move a point around the circle to see that the inscribed angle stays the same, then discover why a tangent is perpendicular to the radius.
Shape Moves and Congruence
Slide, flip, and turn shapes to match the target, and discover that two reflections make a rotation.
Sine and Cosine Rules
See how the circumcircle’s diameter stays the same as the angles change, then use the included angle to find the missing side.
Surface Area & Volume of Cones and Spheres
Fill a cone into a cylinder and unfold its lateral surface into a sector to see why the volume is 1/3 and why a sphere fills 2/3 of its cylinder.
Prisms and Pyramids
Change the base shape and switch between prisms and pyramids to count faces, edges, and vertices and see each net unfold.
Geometric Constructions — Drawing with a Compass
Construct perpendicular and angle bisectors with straightedge and compass, and see why the radius must exceed half the segment.
Integrals and Volumes of Revolution
Rotate curves and stack cross-sections to compute volume by definite integration, and confirm the 3:2:1 ratio of cylinder, hemisphere, and cone.
3D Coordinates and Space Figures
Place points with three coordinates, apply the Pythagorean theorem twice to measure distance in space, and see how equidistant points form a sphere.
Conics: Ellipse, Parabola, Hyperbola
Drag points to see how a constant sum or difference of distances to two foci, or equal distance to a point and a line, produces ellipses, parabolas, and hyperbolas.
Vector Addition and the Dot Product
Add two vectors tip to tail, read magnitude and direction from their components, and judge the angle between them by the sign of the dot product.
Angles, Ratios and Patterns
Turn the protractor to measure angles, simplify ratios into percentages, and work out the next number in a pattern.
Measuring Angles with a Protractor
Read the protractor scale whose 0 touches a side, then open an angle to watch it turn from acute to right to obtuse.
Area and Units
Tile and count 1 cm squares, then stretch each side to see why 1 m² is 10,000 cm², not 100. 🍴 Remix it to swap the last tab's four problems for your own class's.
Volume and Surface Area of Cuboids
Change length, width, and height to stack unit cubes for volume, then unfold the box to work out its surface area. 🍴 Remix it to swap the last tab's four problems for your own class's.
Classifying Triangles and Quadrilaterals
Change angles and vertices to see how triangles and quadrilaterals are named by their properties, and how those names overlap. 🍴 Remix it to swap the last tab's four problems for your own class's.
Parallel Lines and Angles
Tilt the transversal to compare corresponding and alternate angles, and see which ones change once the lines stop being parallel.
Triangle Congruence Conditions
Pick SSS, SAS, ASA, AAA or SSA and drag the sliders to see whether the triangle is uniquely determined or several different ones appear.
Volume of a Cylinder
Change the radius and height to stack the base area upward and work out a cylinder's volume.
Platonic Solids
Rotate the five Platonic solids to count faces, vertices and edges, and check that V-E+F=2 always holds.
Interior Angles of Polygons
Split polygons into triangles to see why the interior angles add up to 180°×(n−2), then work out one angle of a regular polygon.
Pythagorean Theorem
Squares drawn on a right triangle's sides show a²+b²=c² as areas, so you can solve for a missing side and test Pythagorean triples like 3-4-5.
Geometric Similarity: Length, Area & Volume
Adjust the scale factor k to see corresponding sides grow by k, areas by k², and volumes by k³ on grids and cubes.
Sectors: Arc Length & Area
Adjust the radius and central angle to see how arc length and sector area scale with θ/360.
Angles of Polygons
Change the number of sides to split a polygon into triangles and find the interior angle sum, then see the exterior angles always total 360°.