题目内容
如图,小正方形的边长均为1,则下列图中的三角形(阴影部分)与△ABC相似的是( )

| A. | B. | C. | D. |
如图:AB=
=
,AC=
=
,BC=2,

A、∵DE=
=
,DF=
=
,EF=1,
∴
=
=
=
,
∴△DEF∽△BAC,
故A选项正确;
B、∵MN=
=
,MK=
=
,NK=3,
∴
=
,
=1,
=
=
,
∴△MNK与△ABC不相似,
故B选项错误;
C、∵PQ=
=2
,PR=
=
,QR=1,
∴
=
=
,
=
,
=
,
∴△PQR与△ABC不相似,
故C选项错误;
D、∵GH=
=
,GL=
=
,HL=2,
∴
=
,
=
,
=
,
∴△GHL与△ABC不相似,
故D选项错误.
故选:A.
| 32+12 |
| 10 |
| 12+12 |
| 2 |
A、∵DE=
| 12+22 |
| 5 |
| 12+12 |
| 2 |
∴
| AB |
| DE |
| AC |
| EF |
| BC |
| DF |
| 2 |
∴△DEF∽△BAC,
故A选项正确;
B、∵MN=
| 12+22 |
| 5 |
| 12+12 |
| 2 |
∴
| AB |
| NK |
| ||
| 3 |
| AC |
| MK |
| BC |
| MN |
| 2 | ||
|
2
| ||
| 5 |
∴△MNK与△ABC不相似,
故B选项错误;
C、∵PQ=
| 22+22 |
| 2 |
| 12+22 |
| 5 |
∴
| AB |
| PQ |
| ||
2
|
| ||
| 2 |
| AC |
| QR |
| 2 |
| BC |
| PR |
2
| ||
| 5 |
∴△PQR与△ABC不相似,
故C选项错误;
D、∵GH=
| 22+32 |
| 13 |
| 12+22 |
| 5 |
∴
| AB |
| GH |
| ||
| 13 |
| BC |
| GL |
2
| ||
| 5 |
| AC |
| HL |
| ||
| 2 |
∴△GHL与△ABC不相似,
故D选项错误.
故选:A.
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