congruent triangle!!!

Directions: When attempting to prove triangles congruent, it is important to satisfy all of the conditions of the congruent triangle method you are using. This activity is designed to help you organize your thinking about how the parts of a congruent triangle proof will come together. In each problem below, examine the diagram and the GIVEN information. You may wish to draw the diagrams on paper so that you can mark off the information.

Determine the method needed to prove the triangles congruent.
(ASA, SAS, AAS, SSS, or HL for right triangles only)

Check to see if you have the correct method by looking at the Method for Congruent Triangles box at the bottom of the chart.

Each of the three components needed to support the chosen method appear to the left of their corresponding Statement.

Decide what Reasons can be used to support your decisions.



This first problem is an easy problem designed to let you see how this activity is going to work. Look carefully at the problem before continuing. If you click on the answer in the drop down box, it will remain visible.

三角形的全等

如果把兩個三角形疊在一起，能使他們所有頂點、邊和角都完全重和，我們就說這兩個三角形全等，也就是說，這兩個三角形是完全一模一樣的。這時候疊和在一起的頂點叫做對應頂點；疊和在一起的邊叫做對應邊；疊和在一起的角叫做對應角。比方說，有一對雙胞胎，我們就說，兩人的眼睛是「對應眼睛」，鼻子是「對應鼻子」，右手是「對應右手」，因為這些都是他們一樣的地方。

如果△ABC和△DEF全等，我們將它記為：

△ABC△DEF

其中符號「」讀做「全等於」。

此時不一定表示A的對應點是D，不過如果已經知道他們的對應關係，通常會照對應的順序來寫。

結論：若兩三角形全等，則對應邊相等，對應角也相等。

那麼，要怎麼看出兩個三角形全等，是否所有的對應邊相等，對應角相等，才可以說他們全等？因為要一個一個去檢查的話，共要檢查六個條件，實在很累人，有沒有條件是可以省略不必檢查的？

為了易於記錄我們已知的條件，所用「S」表示邊，「A」表示角，邊他們各是英文單字的字首。（邊的英文是side，角的英文是angle）

如果已知三角形一邊的長，用S來表示，已知兩邊的長，用S S來表示。

2009-03-13 17:42:41 補充：
希望可以幫到你:)