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numbers and algebraic expressions
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function and its properties
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quadratic function
polynomials
rational function
exponential function
logarithm
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derivative and integral of functions
trigonometry
plane geometry
analytic geometry
solid geometry
combinatorics
probability
elements of statistics
kropki game

Rhombus is parallelogram with equal sides. The perimeter rhombus: p = 4a. The are of a rhombus: A = ah; A = a^2sinα; A = e * f / 2. The angles in a rhombus: α + β = 180°. The diagonals in a rhombus. The diagonals in a rhombus intersection at a right angle. The point of intersection divides diagonals into equal parts.