POINT REFLECTIONS Review Mrs. Erickson A B C B’ A’ C’ Point Reflections.

Line reflections

Point ReflectionsReviewMrs. Erickson

ABCBACPoint ReflectionsPoint ReflectionsWhat is preserved?

distance is preserved

angle measure is preserved

midpoint is preserved

collinearity is preservedThe figure is always congruent to its image.Rp = the reflection thru point p

Rp(A)=A the image of A under a reflection in point P is AReflect thru the origin Find A:A (3,5)

Reflect thru the origin Find B:B (-2,4)

yPoint ReflectionsxA (3,5)A (-3,-5)B (-2,4)B (2,-4)Reflect thru the origin Find A:A (-3,2)

Reflect across x-axisFind B:B (-3,2)

Reflect across y-axisFind C:C (-3,2)

yPoint ReflectionsxC (3,2)B (-3,-2)(-3,2)A (3,-2)A reflection in the origin is the same as first reflecting across the x-axis, then across the y-axis.

Point ReflectionsDone!Little Boy: My math teacher is crazy.

Mother: Why?

Little Boy: Yesterday she told us that five is 4+1. Today she is telling us that five is 3+2.