Current location - Training Enrollment Network - Mathematics courses - The third grade math "rotation" topic! Waiting online, 100, plus points if you get it right!
The third grade math "rotation" topic! Waiting online, 100, plus points if you get it right!
1. Connect CQ, Minnesota.

From the topic, BN=NQ, AM=MP, N, M is the midpoint between AC and BC, Mn//QC, Mn//CP.

So QC//CP, so Q, C and P are on the same straight line.

2. Solve the coordinates of C, that is, solve the symmetry point of C about O..

C is (1, 3/2)

Find the coordinate of d as (2,3/2) and let BD be y = kx+b.

Bring in the coordinates of b and d, b=0, k=3/4, and the straight line is y = (3/4) x.

3. Make AG perpendicular to AF, and extend BC to make AG cross with G..

Because ∠GAB+∠BAE+∠EAF=90 degrees, ∠BAE+∠EAF+∠FAD=90 degrees.

So ∠GAB=∠FAD, and because AB=AD, ∠ABG=∠ADF.

So △ABG is equal to △ADF.

So BG=DF, ∠AGB=∠AFD.

Because AB//CD has ∠BAF=∠ADF, ∠AGB=∠BAF.

Because AF is the bisector of ∠EAD.

So ∠GAE =∠ BAFF

So ∠GAE =∠ age, that is, AE=GE=BG+BE=DF+BE.

(1) △ CBD is an equilateral triangle.

The proof is as follows: α+∠HCB=∠HCB+∠BCD=90 degrees.

∠BCD=60 degrees, BC=CD, so) △CBD is an equilateral triangle.

(2) Let the H coordinate be (a, 4)AH=HC.

A squared =(6-a) squared +4 squared.

Get a=3/ 13.

That is, h (3/13,4)

With y=kx+b, the coordinates of h and c can be brought in, and the analytical formula of HC can be obtained.

5. (2) Delta ABC and Delta △CDE are equilateral triangles.

After rotation, a, c and d are on the same straight line.

From the perspective of rotation, BC=AC, CE=CD, and ∠BCA=∠ECD=60 degrees.

Therefore, △ABC and △CDE are equilateral triangles.

(3)△ACN and △BCM are congruent, which is known by rotation.

MN//BD

Because △ACN and △BCM are congruent, there is CM=CN.

Because ∠ACE=60 degrees

So △MCN is an equilateral triangle.

From the perspective of relationship, MN//BD

These are all typed by myself ~ for the landlord's reference ~ ~ The key is to make auxiliary lines and have a conceptual understanding ~ Come on ~