In the 1960s he began developing equations for predicting the reflection of electromagnetic waves from simple two-dimensional shapes.

A perimeter is a path that surrounds a two-dimensional shape.

The area of an arbitrary two-dimensional shape can be determined using a measuring instrument called planimeter.

A circle is a round two-dimensional shape, shaped like the letter o.

Unless stated, positions are the centroids of the two-dimensional shapes made by the countries.

Our visual world is an immediately present one of colours and flat two-dimensional shapes.

For example, two-dimensional shapes like circles will fit inside of a flat plane.

Circles, triangles, rectangles, and so forth describe two-dimensional shapes that are often found in the real world.

This book also showed how to measure different two-dimensional shapes and three-dimensional solids.

In geometry, a semicircle is a two-dimensional geometric shape that forms half of a circle.