He drew an equilateral triangle shape.

This orthophoto shows the details of the terrain very clearly.

There are times when we perform calculations with the haversine in trigonometry.

He is an expert in orthoepy, teaching pronunciation.

A positive-definite matrix is an important concept in linear algebra.

My family consists of four people.

I drew a four in mahjong.

He bought six apples.

The Y chromosome carries the genes that determine maleness.

I inherited my X chromosome from my mother.