1, FG∨AD, GH∨BC is fg/ad = CG/AC; GH/BC=AG/AC means FG/AD+GH/BC= 1, FG/80+GH/ 120= 1① To make the planting area equal to the planting area, we can use the formula GH * AK = GH (AD-FG) = (Be+CF. Combine two equations; It is concluded that when FG=40, GH=60 and FG=40, the area planted with grass = the area planted with flowers.

2、T-S△ABC = T△AGH+T△BEH+T△CFG+T-EFGH = 1/2 * 6 * AK * GH+ 1/2 * 10 *(BE+CF)* FG+4 * FG * GH = 3GH(80-FG)+5FG( 120-GH)+4FG * GH = 240 GH+600 FG

FG/80+GH/ 120= 1 can be converted into 3FG+2GH=240, so let FG=x and GH=(240-3x)/2 be substituted.

T-S△ABC = 28800+240x-4x (240-3x)/2 = 6 (x2-40x+4800) = 6 [(x-20) 2+4400], that is, there is a minimum value when the minimum value of T-S △ ABC FG=x=20.