As shown in the figure, in the triangle AOB, the coordinates of a and B are (- 4, - 6), (- 6, - 3), respectively. Calculate the area of the triangle AOB (hint: the area of the triangle AOB can be regarded as the area of a trapezoid minus the area of some small triangles)

As shown in the figure, in the triangle AOB, the coordinates of a and B are (- 4, - 6), (- 6, - 3), respectively. Calculate the area of the triangle AOB (hint: the area of the triangle AOB can be regarded as the area of a trapezoid minus the area of some small triangles)

S △ AOB = s trapezoidal bcdo - (s △ ABC + s △ OAD) = 12 × (3 + 6) × 6 - (12 × 2 × 3 + 12 × 4 × 6) = 27 - (3 + 12) = 12

As shown in the figure, the coordinates of a and B in △ AOB are (2,4), (6,2) respectively. Find the area of △ AOB. (the area of △ AOB can be regarded as the area of a rectangle minus the area of some small triangles.)

The intersection of CE and CF is C, and the perpendicular foot is e, f ∵ a (2,4), B (6,2) ∵ OE = AC = 4, EA = CB = BF = 2, of = 6, ∵ secfo = 6 × 4 = 24 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp (2) s △ AOE = 12 × 4 × 2 = 4 (4 points)

As shown in the figure, in the triangle AOB, the coordinates of two points a and B are (2,4) and (6,2), respectively
emergency

The answer is shown in the picture

As shown in the figure, in the triangle AOB, the coordinates of a and B are (2,5), (6,8) respectively, and the area of the triangle AOB is calculated

The idea of this topic is as follows:
Change the coordinate into length (make the vertical line of X and Y axes according to the known point)
Transform the contents of coordinates into right triangle or right trapezoid to solve the problem
Make a vertical line (vertical) of X axis through a and B respectively,
Observe the triangle, is a quadrilateral (trapezoid + right triangle) minus a right triangle
Just draw a picture according to the above method