Basic 2D Shapes
Shapes are all around us!
Let's learn about flat shapes.
Circle
A circle is a flat shape. Its edge is called the circumference. All points on the circumference are the same distance from the center.
Properties:
- No corners or sides
- Center - the point in the middle
- Radius - distance from center to edge
- Diameter - this is two radii; it goes through the center
Examples: ball, wheel, plate, coin
How to draw: trace around a round object or use a compass
Fun fact: a circle has infinitely many lines of symmetry
Square
A square has 4 equal sides and 4 right angles.
Properties:
- All sides are equal
- 4 angles of 90°
Examples: tile, checkerboard square, window
How to draw: draw 4 equal sides at right angles; use a ruler and set square
Fun fact: the diagonals of a square are equal and cross at right angles
Rectangle
A rectangle has 4 sides: 2 long and 2 short, and 4 right angles.
Properties:
- Opposite sides are equal and parallel
- 4 angles of 90°
Examples: book, screen, door
How to draw: draw two equal lines and connect them with parallel lines at right angles
Fun fact: the diagonals of a rectangle are equal
Triangle
A triangle has 3 sides and 3 angles.
Properties:
- The sum of angles equals 180°
- Can be equilateral, isosceles, or scalene
Examples: road sign, slice of pizza
How to draw: draw three lines and close them into a shape
Fun fact: the heights of a triangle meet at one point (orthocenter)
Oval
An oval is like a circle, but it is stretched out - like an egg shape.
Properties:
- No corners
- Has a long axis and a short axis
Examples: egg, running track at a stadium
How to draw: trace around an egg shape or use an oval template
Fun fact: an oval usually has 2 lines of symmetry