I. Analysis
Because the four sides of a square are equal in length, the circumference of a square is four times the length of its sides. Calculation formula: If S is the area of a square, C is the perimeter of the square, A is the side length of the square, and V is the diagonal of the square, then: C = 4as = a? =V？ ÷2。
Second, the introduction of the square
A group of parallelograms with equal adjacent sides and a right angle is called a square. Square, also called regular quadrilateral, is a special parallelogram. A square has all the characteristics of a rectangle and a diamond.
Third, the area of the square.
Square area = square of side length s = a× a (s stands for square area and a stands for square side length). Half the diagonal product.
Fourth, the definition of mathematical formula
It is an expression that people find some connection between things in nature and express it in some way. It represents the equal or unequal relationship between the quantities of different things in nature, accurately reflects the internal and external relations of things, and is the basis for us to reach another thing from one thing, so as to better understand the essence and connotation of things.
Square knowledge point
1, edge:
Two groups of opposite sides are parallel respectively; All four sides are equal; Adjacent sides are perpendicular to each other.
2. Internal angle:
All four angles are 90, and the sum of internal angles is 360.
3. Diagonal line:
Diagonal lines are perpendicular to each other; Diagonal lines are equal and equally divided; Each diagonal bisects a set of diagonal lines.
4. Symmetry:
It is both a central symmetric figure and an axisymmetric figure (with four axes of symmetry).
5, special properties:
A diagonal of the square divides the square into two isosceles right triangles, and the included angle between the diagonal and the side is 45; The two diagonal lines of a square divide it into four congruent isosceles right-angled triangles.
6. Other attributes (1):
A square has all the properties and characteristics of parallelogram, rhombus and rectangle.
7. Other attributes (2):
A square is a special rectangle and a square is a special diamond.