Scale Factor to go from F to G = 3/4
Scale Factor to go from G to F = 4/3
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Explanation:
Note the sides labeled 4 and 3 are both opposite the angles that have two tickmarks. Therefore, these two sides correspond to one another.
Because of the similar triangles, the corresponding sides are in proportion. The scale factor is 3/4 meaning the smaller triangle has side lengths 3/4 as large compared to the larger triangle.
Put another way, we have a 25% reduction in the side lengths because 3/4 = 75% and 100% - 75% = 25%
So far, all of this applies when figure F is the preimage and G is the image. If we reverse things, then apply the reciprocal to 3/4 to get 4/3. Now G is the preimage and we go from smaller to larger.
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Side notes:
- If the scale factor is smaller than 1, but still positive, then the image is smaller than the preimage. We have an image reduction.
- If the scale factor is larger than 1, then the image is larger than the preimage. We have an image enlargement.
