The answer is a triangle . All other shapes have more than one line of symmetry. The line of symmetry of a triangle is a vertical line drawn from the top point to the midpoint of the base.
A triangle. Down the middle no where else
An isosceles triangle has exactly one line of symmetry, which runs from the top vertex to the midpoint of the base. This line divides the triangle into two equal halves. Other shapes, like squares and circles, have multiple lines of symmetry, making them different from the isosceles triangle.
;