Sennenji is my best friend.

He drew an equilateral triangle shape.

He made a model of a regular tetrahedron.

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.

He started a business without a plan, forgetting the lesson of 'peach and chestnut seeds take three years to bear fruit, persimmons eight years.'

I use a set square to draw shapes.

In chemistry class, I learned about acid anhydride.