Reflection

Yes

No

Reflection

Yes

No

Line Symmetry

A figure has line symmetry if a line can be drawn on a it which creates

two sides that are reflections of one another

The red line (line of symmetry) creates two triangles which are reflections of one another. Therefore, this triangle has line symmetry

Do these figures have line symmetry? If so, draw the lines

YESYES

NO

Do these figures have line symmetry? If so, draw the lines YES

NO

Do these figures have line symmetry? If so, draw the lines

YES

YES

Point out objects in this room that have line symmetry

Draw 1 figure that has 1 line of symmetry

Draw one figure that has more than 1 line of symmetry

Line of ReflectionWhen you reflect a figure in a line, the line is

called the line of reflection

KEY CONCEPTTo reflect a point in the x-axis, multiply its y-coordinate by -1Ex: (x,y) turns into (x,-y)Ex: (2,3) turns into (2, -3)

To reflect a point in the y-axis, multiply its x-coordinate by -1Ex: (x,y) turns into (-x,y)Ex: (2,3) turns into -2,3)

Examples using Y axisOriginal Points:1,31,13,13,3

Reflected Points:-1,3-1,1-3,1-3,3

Multiply all the X Coordinates with -1

Examples using X axisOriginal Points:1,31,13,13,3

Reflected Points:1,-31,-13,-13,-3

Multiply all the Y Coordinates with -1

REFLECT THIS IMAGE ON THE X AXIS

POINTS:-1,4-1,1-4,4

REFLECT THIS IMAGE ON THE X AXIS

POINTS:-1,4-1,1-4,4

Reflected Points-1,-4-1,-1-4,-4

REFLECT THIS IMAGE ON THE Y AXIS

POINTS:-1,4-1,1-4,4

REFLECT THIS IMAGE ON THE Y AXIS

POINTS:-1,4-1,1-4,4

Reflected Points1,41,14,4

GRAPH THESE POINTS THEN REFLECT THEM ON THE X AXIS

1,-14,-11,-34,-3

Correctly Graphed

Correctly Graphed

Reflected Points:1,14,11,34,1

Homework

PAGE 434Guided Practice #3

PAGE 435Skill Practice # 6,7,8