The formula of trapezoid area and perimeter trapezoid area is (upper bottom+lower bottom) × height ÷2.
Expressed in letters: (a+b)×h÷2
The area formula of trapezoid is 2: midline × height.
Expressed in letters: L H (L stands for the length of neutral line)
In addition, the trapezoid with diagonal lines perpendicular to each other: diagonal x diagonal ÷2.
The formula of the perimeter of the trapezoid is: upper bottom+lower bottom+waist+waist, expressed in letters: L = A+B+C+D.
The circumference formula of isosceles trapezoid is: upper bottom+lower bottom +2 waist, expressed in letters: a+c+2b.
Trapezoidal attribute 1. The line segment connecting the midpoint of the diagonal of the trapezoid is equal to half of the two bases.
2. In trapezoidal ABCD, if ab∨CD, m is the midpoint of BC, and MN⊥AD is in n, then s- trapezoidal ABCD = Mn ad = 2s △ and.
3. If the two angles of the trapezoid on the same base are 40 and 70 respectively, the sum of the other base and the waist is equal to the length of this base.
4. If the bisector of the inner angle on the same side of the trapezoid intersects the midpoint of the other waist, the sum of the upper and lower bottoms is equal to the length of this waist.
5.？ The midpoint connecting line between the trapezoidal upper and lower soles is less than half of the sum of the two waistlines.
6. The sum of two base angles on the same base is a trapezoid with 90 degrees, and the connecting line between the midpoint of the upper and lower bases is equal to half of the midpoint of the upper and lower bases.