Rectangular and square are quadrangles, and they have the same point: the opposite sides are equal, and all four corners are right angles. Difference: Only the opposite sides of a rectangle are equal. Through observation and comparison, we can intuitively understand the characteristics of quadrangles, and we can use the characteristics to distinguish which graphics are quadrangles.
You can draw a quadrilateral on a bitmap or grid paper, and you can circle a quadrilateral on the nail board; All four sides of a square are equal. Combined with the life situation, we can initially perceive the characteristics of parallelogram and distinguish which graphics are parallelogram. Can draw parallelogram on bitmap or grid paper, and can circle parallelogram on nail board. The connection and difference between parallelogram and rectangle.
Estimate:
1, parallelogram definition: A parallelogram with two groups of opposite sides parallel to each other is called a parallelogram.
2. The nature of parallelogram: the opposite sides of parallelogram are equal; The diagonals of parallelogram are equal; Diagonal bisection of parallelogram.
3. Determination of parallelogram: two groups of quadrangles with equal opposite sides are parallelograms; Quadrilaterals whose diagonals bisect each other are parallelograms; Two groups of quadrangles with equal diagonal are parallelograms; -A set of parallelograms whose opposite sides are parallel and equal is a parallelogram.
4. The midline of the triangle is parallel to the third side of the triangle, which is equal to half of the third side.
5. The midline of the hypotenuse of a right triangle is equal to half of the hypotenuse.