24. The area of the shaded part in the problem is equal to the sum of the areas of two squares minus the areas of three blank triangles (triangle BDE, triangle ABG and triangle FGE respectively), so the formula can be listed:

10* 10+ 12* 12-( 1/2)* 12*( 10+ 12)-( 1/2)* 10* 10-( 1/2)* 12*( 12- 10)

The result: 50 square centimeters.

25. You can find a right-angled trapezoid in the lower right corner. Triangle A and this trapezoid form a rectangle with a length of 6 cm and a width of 4 cm, while triangle B and this trapezoid form a triangle with a base length of 6 cm and a height of X cm. Then the area difference between triangle A and triangle B can be converted into the area difference between this rectangle and big triangle, and the equation can be listed as follows:

4*6-( 1/2)*6*x=6

Solution: x=6

(elite education)