Mr. Kaku is my best friend.

One angle of this triangle is 90 degrees.

He was building a sand castle on the seashore.

He disturbed my heart.

Generally, this character is often used in puzzle games.

His social status is very high.

The inner core of the Earth is mainly composed of iron and nickel.

He warned about the dangers of nuclear warheads.

A straight angle is 180 degrees.

He has expertise in maritime affairs.