求阴影部分的面积（空白部分面积为80平方厘米）。(q4I*F9m(P5R
(q4I*F9m(P5R
算式：提示3P:N0h+V'\(C6y(K(q4I*F9m(P5R
答：阴影部分面积是1n7m;x:u*`1w4@平方厘米。(q4I*F9m(P5R