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Special review of plane mathematics answers after primary school graduation.
1, Uncle Liu surrounded a trapezoidal vegetable field with a bamboo fence, with one side against the wall (as shown in the figure), and the fence was 48m in total. If you harvest 10km of cabbage per square meter, how many Jin of cabbage can you harvest on this land? (The angle between the wall with trapezoid height of 15m and the other side of the trapezoid is 45 degrees. )

Answer: I can't answer because I don't see the picture and I don't know the specific situation, because the trapezoid can be isosceles trapezoid, right-angled trapezoid and so on.

Now suppose that the figure is a right-angled trapezoid and the wall is the bottom: (√2: root number 2)

The vertical line from the point on the hypotenuse to the wall height h, h= 15m,

Because the angle between the wall and the hypotenuse of the trapezoid is 45 degrees, it is an isosceles right triangle.

According to Pythagorean Theorem, the length of hypotenuse is 15√2,

The length of the upper bottom edge = 48-15-15 √ 2 = 33-15 √ 2,

The length of the bottom wall is15+33-15 √ 2 = 48-15 √ 2.

Trapezoidal area = (33-15 √ 2+48-15 √ 2) *15/2 = (81+30 √ 2) *15/2.

Chinese cabbage harvest: (81+30 √ 2) *15/2 *10.

2. The waiter laid a square tablecloth on the round dining table with a diameter of 1.6m and a height of1m.. The four corners of the tablecloth just hit the ground, and the area of the tablecloth is () square meters.

Answer: The diagonal length of the tablecloth is1+1.6+1= 3.6m. Let the side length of the tablecloth be A and the area of the tablecloth be a 2 (A 2 stands for square).

According to Pythagorean theorem:

a^2+a^2=3.6*3.6

A 2 = 6.48 square meters