Geometry is a kind of mathematics that studies the size, shapes, and positions of things. There are flat (2D) shapes and solid (3D) shapes in geometry. Squares, circles and triangles are some of the simplest shapes in flat geometry. Cubes, cylinders, cones and spheres are simple shapes in solid geometry.
Geometry can be used to calculate the size and shape of many things. For example, geometry can help people find:
- the surface area of a house, so they can buy the right amount of paint
- the volume of a box, to see if it is big enough to hold a liter of food
- the area of a farm, so it can be divided into equal parts
- the distance around the edge of a pond, to know how much fencing to buy.
Geometry began as the art of measuring the shape of land so that it could be shared fairly between people. The word "geometry" means "to measure the land". It has grown from this to become one of the most important parts of mathematics. The Greek mathematician Euclid wrote the first book about geometry. Geometry is one of the oldest branches of mathematics.
Geometry starts with a few simple ideas that are thought to be true, called axioms. Such as:
- A point is shown on paper by touching it with a pencil or pen, without making any sideways movement. We know where the point is, but it has no size.
- A straight line is the shortest distance between two points. For example, Sophie pulls a piece of string from one point to another point. A straight line between the two points will follow the path of the tight string.
- A plane is a flat surface that does not stop in any direction. For example imagine a wall that extends in all directions infinitely.
A tiling of the hyperbolic plane
Geometry for Kids. Kiddle Encyclopedia.