The area of the trapezoid is equal to the sum of the upper and lower bottoms multiplied by the height divided by two. The letter A represents the upper bottom of the trapezoid, the letter B represents the lower bottom of the trapezoid, and the letter H represents the height of the trapezoid. It can be concluded that the area letter st of the trapezoid is equal to the sum of A and B multiplied by H divided by 2.

Trapezoidal area = (upper bottom+lower bottom) × height ÷2, which can be deduced by methods such as folding, dividing and cutting. If S is used to represent the trapezoidal area, A is used to represent the upper bottom, B is used to represent the lower bottom, and H is used to represent the height, the formula for calculating the trapezoidal area is: S = (a+b) H ÷ 2.

Definition of trapezoid

Trapezoid is a geometric figure in mathematics, which refers to a group of quadrangles with parallel opposite sides. The quadrilateral is composed of convex quadrilateral and concave quadrilateral, and the trapezoid is convex quadrilateral.

Trapezoid is a common kind of plane geometry, and Euclid is the first person to create a relatively complete geometric mathematical theory in history. His book The Elements of Geometry is an early masterpiece in the history of mathematics, which marks the establishment of Euclidean geometry.

In a trapezoid, two parallel sides are called the bottom of the trapezoid, two non-parallel sides are called the waist of the trapezoid, and the vertical line between the two bottoms of the trapezoid is called the height of the trapezoid. Isosceles trapezoid and right-angled trapezoid are two special trapezoid. The isosceles trapezoid is called isosceles trapezoid; A trapezoid whose waist is perpendicular to the bottom is called a right-angled trapezoid.

In plane geometry, there are parallelogram and trapezoid-like rectangle. They are all quadrilaterals with a set of parallel opposite sides. In addition, there is a similar figure, which is a curved trapezoid. By calculating its area, a definite integral can be defined.

Trapezoids are widely used in mathematics. In plane geometry, trapezium is usually judged by definition, and there are many common trapezium objects in daily life. In terms of architecture, the trapezoidal architectural style can make the building foundation stable and facilitate height improvement.

When melting, the material absorption area of the flat trapezoidal inner runner is small, which is helpful to play the role of slag retention of the runner and can be used for modeling black or non-ferrous alloy castings.