Sarah was thinking of a number. Sarah doubles it and gets an answer of 4.5. What was the original number?
2 answers:
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General Idea:
When we are given a point P(x, y) centered at origin with a scale factor of k, then the dilated point will be given by P' (kx, ky)
Applying the concept:
In the diagram given, the coordinate of C is (6, 3). Triangle ABC is being dilated with the center of dilation at the origin. The image of C, point C' has coordinates of (7.2, 3.6).
If C (x, y) centered at origin with a scale factor of k, then the dilated point will be given by C' (kx, ky)
We know &
Substituting 6 for x in the equation , we get
.
Dividing 6 on both sides
Simplifying fractions on both sides
Point A from the diagram is (-3, 3)
x-coordinate of A' =
y-coordinate of A' =
Point A' is given by (-3.6, 3.6)
Conclusion:
<u>Scale factor of dilation is 1.2</u>
<u>The coordinates of point A' is (-3.6, 3.6)</u>