Solution: Set the planned demolition area X and the planned new construction area Y..

X+Y=7200

( 1+ 10%)X+80%Y=7200

solve

X=4800，

Y=2400

(2)

Fund for the proposed new school building: 700 * 2400 = 1 680,000 yuan.

Fund for planned demolition of school buildings: 80 * 4,800 = 384,000 yuan.

School building construction and demolition plan funds * * *: 65,438+0,680,000+384,000 = 2,064,000 yuan.

Actual fund for new school building: 80% * 2400 * 700 =1344,000 yuan.

Actual funds for demolishing school buildings: (1+10%) * 4,800 * 80 = 42,240 yuan.

Actual funds for building and dismantling school buildings * * *:1344000+4240 =1386240 (RMB).

The saved funds are: 2064000- 1386240=677760 (yuan).

Green area saved: 677,760/200 = 3,388.8 square meters.

Answer: In the actual demolition and construction project, the remaining funds are used for greening, which is 3,388.8 square meters.