Euclidea 1~7 글 모음 http://gall.dcinside.com/mgallery/board/view/?id=math&no=2380


viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5314e23aa03c365b44574ac1b

점을 지나는 직선이 교차하는 직선들과 이등변삼각형이 되게 하는 문제에요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5631d76fc059666b54574ac1b

이등변 삼각형이니까 답 하나는 쉽게 보여요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5311525ab51c764be4574ac1b

이것이겠죠?

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5354875f905cc63be4574ac1b

두번째 방법이에요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c561147eab56c067b64574ac1b

초록색 선에 대하여 수직선을 그은 것이에요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5651c75a958c363e44574ac1b

정팔각형을 작도하는 문제에요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5651975ad53cd62b74574ac1b

정팔각형은 내각이 135도이므로 45도를 먼저 만들어요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5611f22ad56c231b64574ac1b

그 다음 꼭짓점을 찾아주고,

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5361477a202cd35b44574ac1b

이어요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5644b22aa00c335b34574ac1b

두번째 방법이에요.

viewimage.php?id=20bcc42e&no=24b0d769e1d32ca73cee85fa11d02831fb456630640f875b0a4c706b466906c92f1cb503cf372c421fe6c58a7657b1f0ddf1c5364c24a957c031b24574ac1b

두 개 있어요.


그럼 바이바이~