point reflections review mrs. erickson a b c b’ a’ c’ point reflections
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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.
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