A triangle whose one angle is a right angle is known as angled triangle.

A triangle may have four vertices.

Any three line segments make up a triangle.

The vertices of a triangle are three collinear points.

An equilateral triangle is isosceles also.

No isosceles triangle is obtuse.

Every right-angled triangle is scalene.

The interior of a triangle includes its vertices.

Each acute triangle is equilateral.