Season 01 • Episode AP10 • Using congruent triangles
0Using congruent triangles
Season 01
Episode AP10 Time frame 1 period
Prerequisites :
Voabularyandnotionsabouttrianglesandangles.Objectives :
•
Use ongruent triangles tosolve problems.Materials :
•
Exerises.1 – Exercises Whole period
Working by pairs, students have to solve some exerises and hand out a paper to the
Using congruent triangles
Season 01
Episode AP10 Document Exercises
Exercise 1
Let
ABC
be asalene triangle,withCBF G
andABDE
two squares built outsideof it 1. Deompose the anglesto prove that∠ CBD = ∠ ABF
.2. Dedue that
△ BCD
and△ ABF
are ongruent.3. Dedue that
AF = DC
.Exercise 2
Let
d
1
andd
2
betwo parallellines, withA
apointond
1
andB
a pointond
2
. LetK
bethe midpoint of the segment
AB
. ThroughK
, draw a line( D )
that intersetsd 1
inM
and
d
2
inN
.1. Prove that the triangles
KAM
andKBN
are ongruent.2. Dedue the positionof
K
onM N
.Exercise 3
Let
ABC
beasalenetriangle,withI
themidpointofBC
.LetB ′
andC ′
betheorthogonal projetions ofB
andC
ontothe medianAI
of the triangle.1. Prove that the triangles
I BB ′
andI CC ′
are ongruent.2. Dedue from the previous question the nature of
BBCC ′
.Exercise 4
Let
ABCD
be a square with enterO
andM
a point on the sideAB
. LetP
be the intersetion ofthe sideAD
and the line perpendiular toCM
throughB
.1. Prove that
∠ DCM = ∠ BM C
and dedue that∠ BCM = ∠ ABP
.2. Dedue that the triangles
M CB
andP BA
are ongruent and thatM B = AP
. 3. Prove that the trianglesOM B
andOP A
are ongruent.4. Dedue that