He requested the cancellation of the contract.

His character is very kind.

His explanation was very clear.

His precise judgment led our project to success.

This figure is an acute triangle.

He yelled at me, looking at me with fury.

He taught me how to calculate the area of an obtuse triangle.

He can sense his surroundings using his tactile hairs.

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

The calculation of the spherical angle is a part of geometry.