1. Draw a text box on white paper.
2. Write "parallelogram and trapezoid" in the text box.
3. Draw secondary titles on both sides, and then add "parallelogram and trapezoid" to the secondary titles.
4. Add a few smaller branches to the branch, and add relevant content, and the mind map about "parallelogram and trapezoid" will be done.
Parallelogram is a closed figure composed of two groups of parallel lines on the same two-dimensional plane. Parallelogram is generally named by the graphic name followed by four vertices.
In Euclidean geometry, a parallelogram is a simple (non-self-intersecting) quadrilateral with two pairs of parallel sides. The opposite sides of a parallelogram are equal in length, and the diagonals of the parallelogram are equal. On the contrary, a quadrilateral with only one pair of parallel sides is a trapezoid. The three-dimensional correspondence of a parallelogram is a parallelepiped.
A trapezoid is a quadrilateral with only a set of parallel opposite sides. Parallel sides are called trapezoidal bottoms: the longer bottoms are called bottoms, and the shorter bottoms are called bottoms; The other two sides are called waist; The vertical section sandwiched between the two base sides is called the height of the trapezoid. A trapezoid whose waist is perpendicular to the bottom is called a right-angled trapezoid. An isosceles trapezoid is called an isosceles trapezoid.
Calculation method of parallelogram and trapezoid
1, the area formula of parallelogram: base times height, that is, the area of parallelogram is equal to base times height.
2. Perimeter of parallelogram: the sum of four sides, that is, the perimeter of parallelogram is the sum of four sides.
3. The sum of the internal angles of the parallelogram: 180 degrees times (number of sides -2), that is, the sum of the internal angles of the parallelogram is 180 degrees times (number of sides -2).
4. Perimeter formula: upper sole+lower sole +2 waist, expressed in letters as L=a+b+2d. The length of the upper bottom is A, the length of the lower bottom is B, the waist length is C and D, and the circumference is L. Because the two waists of the isosceles trapezoid are equal, that is, c=d, L=a+b+2d can be simplified.
5. Area formula: the upper bottom and the lower bottom are added, multiplied by the height, and finally divided by 2. Expressed in letters as s=(a+b)×h÷2. Wherein the length of the upper bottom surface is A, the length of the lower bottom surface is B, the height is H, and the area is S.