An equilateral triangle is an acute-angled triangle, all its angles are 60°. Image caption, ... eg acute-angled, right-angled or obtuse-angled. An acute angle is less than 90°.

Equilateral triangle. ... A right-angled triangle is a triangle where one of the angles is 90 degrees. ... An obtuse-angled triangle is a triangle that has one obtuse angle. Acute-angled triangle.