因为S 1=
1
2 S △ABC,S 2=
4
9 S △ADC,又因S △ABC=S △ADC=
1
2 S 正方形,
则S 1+S 2=12× 12×
1
2 ×
1
2 +
1
2 × 12× 12×
4
9 ,
=36+32,
=68;
答:则S 1+S 2的值为68.
因为S 1=
1
2 S △ABC,S 2=
4
9 S △ADC,又因S △ABC=S △ADC=
1
2 S 正方形,
则S 1+S 2=12× 12×
1
2 ×
1
2 +
1
2 × 12× 12×
4
9 ,
=36+32,
=68;
答:则S 1+S 2的值为68.