Wise men cherish the year, wise men cherish the day, and saints cherish the time. It is good for us to spend time diligently doing the exercises in the eighth grade mathematics textbook of Jiangsu Education Press. The following are the answers to the exercises in the first volume of the eighth grade mathematics textbook of Jiangsu Education Publishing House, which I carefully arranged for you, for reference only.

Answers to the first volume of the eighth grade mathematics textbook Jiangsu Education Edition (1)

The answer to the question 19 in the exercise textbook.

Solution: Figures ① and ⑥ are congruent trigrams. Because there are two groups of corresponding angles in these two triangles, and the sides of the corresponding angle clips are equal, according to ASA, it can be judged that these two triangles are congruent. For the same reason, Figures ② and ④, ③ and ⑤ are also congruent triangles.

The answer to the second question on page 19.

It is proved that ∵O is the midpoint of AB (known),

? AO= BO (definition of midpoint), ∫AC//BD (known),

A=？ B (two straight lines are parallel with equal internal angles).

At △AOC and △BOD,

? △AOC?△BOD(ASA)，

? CO= DO (the corresponding sides of congruent triangles are equal),

That is, o is the midpoint of CD.

Answers to the first volume of the eighth grade mathematics textbook Jiangsu Education Edition (II)

Exercise textbook page 22 1 answer.

1, proving that in △ABE and △ACD,

? △ABE≌ACD(ASA)。

? AD=AE (the corresponding sides of congruent triangles are equal).

DB = AB = AD，EC=AC=AE，

? DB=EC (equivalent substitution)

Practice the answer to question 2 on page 22 of the textbook.

Proof: ABC =? DCB，？ 1=? 2,

DBC=？ ACB，

In △ABC and △DCB,

? △ABC?△DCB(ASA)。

? AB= DC

(The corresponding sides of congruent triangles are equal). Answers to the first volume of the eighth grade mathematics textbook Jiangsu Education Edition (III)