Please calculate the area of this right-angled triangle.

It's difficult to calculate the area of this hexagon.

He is known as an expert in subcritical nuclear experiments.

The Cultural Revolution is a part of China's history.

He claims to have seen an unidentified flying object.

Let's calculate the area of this right-angled triangle.

Old Church Slavonic is the first language written by the Slavs.

Old Church Slavonic is the oldest recorded language of the Slavic group.

I am thinking of learning Levantine Arabic.

The Germanic languages, such as English and German, form the basis of many modern languages.