A spherical TRIANGLE is a triangle that is contained under three arches of a great circle or sphere.
A right-angled TRIANGLE is one which has one right angle.
An acute-angled TRIANGLE is one that has all its angles acute.
An obtuse-angled TRIANGLE is that which has one obtuse angle.
An oblique-angled TRIANGLE is a triangle that is not right angled.
An equilated TRIANGLE is one whose sides are all equal.
| An isosceles TRIANGLE, | - | |
| An equilegged TRIANGLE, |
A triangle that has only two legs or sides equal.
A scalenus TRIANGLE. One that has not two sides equal.
Similar TRIANGLES are such as have all their three angles respectively equal to one another.