A parallelogram with a right angle is called a rectangle. It is a rectangle.

nature

1. All four corners of a rectangle are right angles.

2. The diagonals of rectangles are equal.

3. The sum of squares of the distances from any point on the rectangular plane to its two diagonal endpoints is equal.

4. A rectangle is both an axisymmetric figure and a centrally symmetric figure (the symmetry axis is a line connecting the midpoints of any group of opposite sides).

5. The opposite sides are parallel and equal

6. Divide diagonally.

7. A parallelogram has all the properties.

Definition of diamond

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

nature

Diagonal lines are perpendicular to each other and equally divided;

All four sides are equal;

Diagonal angles are equal and adjacent angles are complementary;

Each diagonal bisects a set of diagonal lines,

The rhombus is not only an axisymmetric figure, but also a centrally symmetric figure.

60 rhombus, the short diagonal is equal to the side length, and the long diagonal is √3 times of the short diagonal.

A diamond has all the characteristics of a parallelogram.

Fraction definition: algebraic expression A divided by algebraic expression B can be expressed as. If part b contains letters, it is called a fraction.

Note: A÷B= =A× =A×B- 1= A? B- 1. Sometimes it is written as a negative exponent, that is, a? B- 1 is only different in form, but there is no difference in essence.

Binary linear equations If there are two unknowns in the equations, and the term containing the unknowns is a linear term, then such equations are called binary linear equations.