Answer: 1/3
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Explanation:
Triangle STV has points at locations
S = (0, 6)
T = (-3, -6)
V = (3, -6)
Triangle S'T'V' has points at locations
S ' = (0, 2)
T ' = (-1, -2)
V ' = (1, -2)
Pick on just one pair of corresponding points. I'll pick on points S and S'
Going from S = (0,6) to S ' = (0, 2), note how the y coordinate has been divided by 3. This is the same as multiplying by 1/3. Therefore, the scale factor is 1/3
We can see this happening with points T and T ' as well
T = (-3, -6) to T ' = (-1, -2) also has each coordinate multiplied by 1/3
The same can be said from V to V' also.
Because the scale factor is 1/3, this means that the side lengths of the image triangle S'T'V' are 1/3 as long as the preimage triangle STV.