Question

Which one of the following has only three lines of symmetry?

• A. Scalene triangle
• B. Isosceles triangle
• C. Equilateral triangle
• D. Right-angled Triangle

Answer 1

The correct option is C

Equilateral triangle

An equilateral triangle has three lines of symmetry, the bisector of the angles are the lines of symmetry.

An isosceles triangle has one line of of symmetry, the line of symmetry is the bisector of the angle contained by the two equal sides of the triangle.

A scalene triangle has no line of of symmetry, because all the sides are unequal.

A right angled triangle has one angle which is $90$ degrees corresponds to one line of symmetry because it bisects the triangle at the angle $90$ degrees in to two equal halves.

Hence , option (c) is correct.