How to calculate the perimeter of parallelogram?

Calculation method of parallelogram perimeter: C=2(a+b).

I. Definition

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

1, parallelogram is a plane figure.

2. Parallelogram belongs to quadrilateral.

3. The parallelogram belongs to the central symmetry figure.

Second, nature.

(1) If a quadrilateral is a parallelogram, then two opposite sides of the quadrilateral are equal.

(Simply stated as "two opposite sides of a parallelogram are equal")

(2) If the quadrilateral is a parallelogram, then the two opposite corners of the quadrilateral are equal respectively.

(Simply stated as "the two diagonals of a parallelogram are equal respectively")

(3) If a quadrilateral is a parallelogram, then the adjacent angles of this quadrilateral are complementary.

(simply described as "complementary adjacent angles of parallelogram")

Third, the verdict

1, two groups of parallelograms with opposite sides are parallelograms (definition judgment method);

2. A group of quadrilaterals with parallel and equal opposite sides are parallelograms;

3. Two groups of quadrangles with equal opposite sides are parallelograms;

4. Two groups of quadrangles with equal diagonal angles are parallelograms (two groups of opposite sides are judged to be parallel);

5. Quadrilaterals whose diagonals bisect each other are parallelograms.

Fourth, auxiliary lines

1, connecting diagonal or translating diagonal.

2. Form a right triangle through the vertical line from the vertex to the opposite side.

3. Connect the diagonal intersection with the midpoint of one side, or cross the diagonal intersection into parallel lines on one side to form a line segment parallel or midline.

4. Connect the line segment between the vertex and the point on the opposite side, or extend the line segment to build a similar triangle or an equal area triangle.

5. The vertical line passing through the vertex constitutes a parallel line segment or triangle congruence as a diagonal line.