He had twenty old coins.

It takes twenty minutes to get to my house.

The 正十六胞體 is one of the regular polytopes in four dimensions.

He is known as a person with learning.

This project has been completed in its entirety.

Euclidean geometry forms the foundation of geometry.

He is an expert in algebraic geometry.

He is an expert in topology.

Riemannian geometry is a field of mathematics that studies geometric objects such as curves and surfaces.

Projective geometry is a branch of mathematics that studies geometric objects such as points, lines, and planes and their relationships.