He was drawing a figure using a set square.

Triangulum is one of the beautiful constellations shining in the autumn night sky.

Traffic cones have been set up due to road construction.

Please throw the leftover food in the triangular sink basket in the kitchen.

I go to the gym every day to build my muscles.

This river is three long.

He likes to take a walk in the park at dusk.

In linear algebra, the upper triangular matrix plays a very important role.

A lower triangular matrix is a matrix where all the elements below the main diagonal are zero.

Finding the Summer Triangle is helpful for remembering constellations.