Self-confidence should be in your heart, and you should make progress when you do the title of the eighth grade math book. I sorted out the answers to the first volume of the eighth grade math book, hoping to help everyone!

The eighth grade mathematics scholars' education edition Volume I answers (1) 14 pages.

1. Solution: ACD=? B.

Reason: Because of the CD? AB，

So △BCD is a right triangle,

? BDC=90？ ,

So what? B+？ BCD=90？ ,

Because again? ACB= 90？ ,

So what? ACD+？ BCD=？ ACB=90？ ,

So what? ACD=？ B (complementary angles of the same angle are equal).

2. Solution: △ADE is a right triangle,

Reason: Because? C=90 .,

So what? A+？ 2=90。 .

Because again? 1= ? 2,

So what? A+？ 1=90? .

So △ADE is a right triangle (a triangle with two complementary angles is a right triangle).

Eighth-grade Mathematicians Education Edition Volume 1 Answer (2) Exercise 12.2

Eighth-grade Mathematicians Education Edition Volume I Answer (III) Page 50.

1. Hint: Do? The bisector of AOB intersects with MN at a point, then the point is point P. (Figure omitted)

2. Prove: As shown in figure 12-3-25, the intersection points P are PF and PG respectively, and the pH is perpendicular to the straight lines AC, BC and AB.

The vertical feet are f, g, H g, H.

∵BD is in △ABC? The bisector of ABC's outer corner, point P is on BD. Pg = ph Similarly, PE=PG. PF=PC=PH。