Summary of English grammar easy test sites in junior high school; Highlights of geometric functions in junior high school mathematics; Explanation of physical and electrical Ohm Theorem and Electric Power in Junior Middle School. parallelogram

Two groups of parallelograms with parallel opposite sides are called parallelograms.

Property: the opposite sides of parallelogram are parallel and equal; Diagonal angles are equal and two adjacent angles are complementary; Diagonal lines will split each other in two.

C (perimeter) =2(a+b)

S (area) =a×h(h is the height on the side of a) or s = ab× sin Ф (Ф is the angle formed by ab).

(2) Rectangle

A parallelogram with a right angle is called a rectangle.

Attributes: A rectangle has all the attributes of a parallelogram. In addition, it has the following properties: all four corners of a rectangle are right angles; Diagonal lines are equal.

C=2(a+b)

S=ab

(3) Diamond shape

A set of parallelograms with equal adjacent sides is called a diamond.

Properties: Diamonds have all the properties of parallelogram. In addition, it has the following special properties: the four sides of a diamond are equal; Diagonal lines are perpendicular to each other, and each diagonal line bisects a set of diagonal lines.

(4) Square

A group of parallelograms with equal adjacent sides and a right angle is called a square.

A square is not only a set of rectangles with equal adjacent sides, but also a diamond with right angles, so it has the properties of both rectangles and diamonds.