mathinschool.com
numbers and algebraic expressions
logic, sets, intervals
absolute value
function and its properties
linear function
quadratic function
polynomials
rational function
exponential function
logarithm
number sequences
limits of sequences and functions
derivative and integral of functions
trigonometry
plane geometry
analytic geometry
solid geometry
combinatorics
probability
elements of statistics
kropki game

Axis of symmetry of figure is a line about which figure is axially symmetric to themselves. That line divides the figure into two identical parts. Examples of figures with one axis of symmetry: isosceles triangle, isosceles trapezoid, kite. Examples of figures with two axes of symmetry: line segment, rectangle, rhombus. Example of figure with three axes of symmetry: equilateral triangle. Example of figure with four axes of symmetry: square. Examples of figures with infinite axes of symmetry: area of a circle, circle. Examples of figures without axes of symmetry: non-equilateral triangle, this parallelogram.