求一数学题的解析As in figure 2,the area of square ABCD is l69cm2,and the area ofthombus BCPQ is 156cm2.Then the area of the shadow part is ( )(A) 23cm2.(B) 33cm2.(C) 43cm2.(D) 53cm2.
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![求一数学题的解析As in figure 2,the area of square ABCD is l69cm2,and the area ofthombus BCPQ is 156cm2.Then the area of the shadow part is ( )(A) 23cm2.(B) 33cm2.(C) 43cm2.(D) 53cm2.](/uploads/image/z/7579952-8-2.jpg?t=%E6%B1%82%E4%B8%80%E6%95%B0%E5%AD%A6%E9%A2%98%E7%9A%84%E8%A7%A3%E6%9E%90As+in+figure+2%2Cthe+area+of+square+ABCD+is+l69cm2%2Cand+the+area+ofthombus+BCPQ+is+156cm2.Then+the+area+of+the+shadow+part+is+%28+%29%28A%29+23cm2.%28B%29+33cm2.%28C%29+43cm2.%28D%29+53cm2.)
求一数学题的解析As in figure 2,the area of square ABCD is l69cm2,and the area ofthombus BCPQ is 156cm2.Then the area of the shadow part is ( )(A) 23cm2.(B) 33cm2.(C) 43cm2.(D) 53cm2.
求一数学题的解析
As in figure 2,the area of square ABCD is l69cm2,and the area of
thombus BCPQ is 156cm2.Then the area of the shadow part is ( )
(A) 23cm2.(B) 33cm2.(C) 43cm2.(D) 53cm2.
求一数学题的解析As in figure 2,the area of square ABCD is l69cm2,and the area ofthombus BCPQ is 156cm2.Then the area of the shadow part is ( )(A) 23cm2.(B) 33cm2.(C) 43cm2.(D) 53cm2.
设CD和PQ的交点为E(自己画一下啊),
正方形ABCD的面积是169cm²,
所以其边长BC为13cm,
而菱形BCPQ的面积是156cm²,
即 156=BC×CE,
求得CE=12cm,
由勾股定理,
CE²+PE²=PC²,
CE=12cm,PC=BC=13cm,解得PE=5cm
所以三角形PCE的面积为12×5/2=30cm²,
故梯形QEBC的面积为156-30=126cm²,
于是阴影部分的面积为:正方形ABCD的面积减去梯形QEBC的面积
169-126=43cm²