The isosceles trapezoid has only one axis of symmetry, that is, the straight line where the midpoint of the upper and lower bottom surfaces lies. The judgment of isosceles trapezoid is as follows: a group of quadrangles with equal and non-parallel opposite sides, and another group of quadrangles with parallel opposite sides are isosceles trapezoid; Two trapezoid with equal angles on the same base are isosceles trapezoid; A trapezoid with equal diagonal lines is an isosceles trapezoid; An isosceles trapezoid is an isosceles trapezoid.

First grade of primary school

Recite the formula table of 99 multiplication and be familiar with the multiplication of single digits.

Second grade of primary school

Improve the multiplication formula table, strengthen the knowledge of senior one, learn the mixed operation of division and basic geometry.

The third grade of primary school

Learn multiplication and commutation laws, geometric area perimeter, time amount and unit. Distance calculation, distribution law, fractional decimal.

Fourth grade of primary school

Line angle natural number integer, prime factor trapezoidal symmetry, fractional decimal calculation.

Fifth grade in primary school

Fractional decimal multiplication and division, algebraic equation and average value, comparative size transformation, graphic area and volume.

Sixth grade of primary school

Proportional percentage probability, circular sector cylinder and cone.