Learn lines, rays and angles of lines, then triangles and four-sided shapes. Build shapes, sort them, solve missions and beat the clock.
Start here. A line goes on forever in both directions. A line segment is a piece of a line with two end points. A ray has one end point and goes on forever the other way. Two lines on a flat page are parallel if they never meet, like railway tracks. They are perpendicular if they cross at a right angle, like the corner of a page.
Triangles. Name a triangle by its sides: equilateral has all 3 sides equal, isosceles has exactly 2 equal sides, scalene has no equal sides. You can also name it by its biggest angle: acute (all angles less than 90°), right (one angle of exactly 90°) or obtuse (one angle more than 90°).
Four-sided shapes. Look at three things: parallel sides, equal sides and right angles. A square has 4 equal sides and 4 right angles. A rectangle has 4 right angles. A rhombus has 4 equal sides. A parallelogram has 2 pairs of parallel sides. In this game a trapezoid has exactly 1 pair of parallel sides. A kite has two pairs of equal sides that sit next to each other.
Most specific name. A square is also a rectangle, a rhombus and a parallelogram. When a question asks for the most specific name, pick the name that tells you the most, so a square is called a square.
Try this above. In Play, move the corners of a four-sided shape until it is a rectangle, then slide one corner and watch the name change. Make a triangle with two equal sides. Make two lines that never meet.
A line has no ends and goes on forever both ways. A line segment has two end points. A ray starts at one point and goes on forever in one direction.
Yes. A square is a rectangle that also has four equal sides. When a question asks for the most specific name, the answer for a square is square.
An equilateral triangle cannot sit exactly on dot-grid points. Use the Side lengths tool at level 2 to make one: set all three sides to the same number.
A shape with exactly one pair of parallel sides. Some books also count parallelograms as trapezoids. We use the exact-one rule here, and questions that ask for the most specific name always give a clear answer.
Pick the level, not the age. "Just starting" is about lines, "I know the basics" is about triangles and "Challenge me" is about four-sided shapes.
No. It is free and needs no account. Your stars are saved in your own browser.