Quadrilaterals and Circle
This page expands on wzory na pola figur by covering more complex quadrilaterals and introducing the circle.
The rhombus is presented first, with its perimeter formula (4 times the side length) and area formula (side length times height).
Definition: A rhombus is a quadrilateral with four equal sides, but angles that are not necessarily right angles.
The circle follows, introducing π (pi) in the formulas. The circumference is calculated as 2πr, where r is the radius, and the area is πr².
Highlight: The value of π is approximately 3.14159, but in calculations, it's often rounded to 3.14 or represented by the symbol π.
The isosceles trapezoid is then shown, with a perimeter formula summing all sides and an area formula using the average of parallel sides multiplied by height.
Vocabulary: An isosceles trapezoid is a trapezoid where the non-parallel sides are of equal length.
The rectangle is presented next, with its perimeter formula as twice the sum of length and width, and area as length times width.
Example: For a rectangle with length 8 cm and width 5 cm, the perimeter would be 2(8+5) = 26 cm, and the area would be 8 * 5 = 40 cm².
Lastly, the kite is introduced, with its perimeter as the sum of two pairs of equal sides and area as half the product of its diagonals.
Definition: A kite is a quadrilateral with two pairs of adjacent sides of equal length.
