More Basic Geometry Terms

Congruence

“CONGRUENT” means EQUAL MEASURE.

~ =

is the symbol for “CONGRUENT”

A

H

~ =

C B J I “Triangle ABC is congruent to triangle HIJ”

Look at these intersecting lines. A

B

M C

AMB BMG

~ = ~ =

G

CMG AMC

When two lines intersect, the congruent angles are called VERTICAL ANGLES.

3

1 4

2

Angles 3 & 2 also are vertical angles.

Angles 1 & 4 are vertical angles.

For polygons to be CONGRUENT, all parts must be congruent.

~ ΔABC = ΔJLK J

A

B

C

L

K

J

A

B

C

L

K

Angles A & J are called corresponding angles.

TRANSFORMATION: The movement of a figure.

A TRANSLATION is when a figure “slides” to a new spot.

F

L

IP

!

A REFLECTION is when a figure “flips” across a line.

A rotation is when a figure “spins” around a point.