Triangles are polygons with three sides.
An acute − angled triangle contains no angles greater than 90°.
e.g. A , B and C are all acute angles.
A right − angled triangle contains an angle of 90°.
e.g. A = 90°
e.g. sides: a = b
angles: A = B
An equilateral triangle is one in which all three sides are of equal length and each interior angle is 60°.
An equilateral triangle has three axes of symmetry.
e.g. sides: a = b = c
angles: A = B = C