Hello, children. Tangram consists of regular figures. There are two slightly larger isosceles right triangles (yellow and red), a parallelogram (light blue), a medium-sized isosceles right triangle (green), a square (khaki) and two small isosceles right triangles (blue and purple).

Since the area is needed, the area formula must be known.

Square area = side length x side Yangtze River Delta area = bottom x height ÷2 flat dead shape area = bottom x height

Now let's start looking for areas one by one.

(large) isosceles right triangle = base x height =8X4÷2= 16

(medium) isosceles right triangle =4X4÷2=8

(small) isosceles right triangle =4X2÷2=4

Parallelogram = base x height =4X2=8

Square = side length x side length (the calculation here is not learned by primary school students, and the side length is irrational)

So, on the other hand, I think that the whole board is known except the square area, so the plastic area is

8X8 - 2X 16-8-4X2-8=8

So the square area is 8.