He is learning calligraphy with a square brush.

We need to calculate the azimuth of this building.

If the angle of incidence is large, the reflection becomes stronger.

A straight angle is 180 degrees.

The dogfish is a type of shark that lives in the deep sea.

The antennae of this insect are very long.

Important information is included in the square brackets of this sentence.

The angle of friction of this material is 30 degrees.

When light enters water, the angle of refraction changes.

The pheasant-tailed jacana, known as 'the ballerina of the water' for its beautiful appearance.