Which figure has exactly four lines of symmetry? isosceles triangle equilateral triangle regular hexagon square

D. Square.

Step-by-step explanation:

We are asked to find the figure, which has exactly four lines of symmetry.

We know that line of symmetry is an imaginary line that passes through the center of the figure and divides the image into two identical parts or mirror images.

We know that square is a regular polygon with four equal side and it has four line of symmetry. Two diagonals of square divides it into identical parts.

The line joining midpoints of opposite sides of square are also lines of symmetry.

Therefore, square is the correct choice.

i found two solutions,   n = 2 • ± √3 = ± 3.4641

step-by-step explanation:

so, converting firstly the mixed fractions to improper fractions and then "adding".