Cambridge International Mathematics

10 Assumed Knowledge (Geometry and graphs)

3 Here are some pairs of congruent geometric figures.

ab

cd

ef

For each pair:

i Identify the side in the second figure corresponding to the side AB in the first figure.

ii Identify the angle in the second figure corresponding to ABC in the first figure.b

CONGRUENT TRIANGLES

Two triangles arecongruentif they are identical in every respect except for position.

The above triangles are congruent.

We write ¢ABC»=¢XYZ, where »=reads “is congruent to”.

When writing this congruence statement, we label the vertices that are in

corresponding positions in the same order.

So, we write ¢ABC»=¢XYZ butnot ¢YXZ or ¢ZYX.

If two triangles are equiangular (have all three angles equal), they are not necessarily congruent.

If one triangle was

cut out with scissors

and placed on the

top of the other, they

would match each

other perfectly.

A

BCP

R Q

A

B C

D

E

F

G

H

A

B

C

M

N

O

A

B

C

D

Q

R

S

T

A

B

C

D

P

M

N

O

A

B

q C

X

Y

q Z

A C D F

B E

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