Use the image to answer the question.
A coordinate grid of quadrant 1 shows 2 plotted triangles of the same shape but different sizes. The x and y axes range from 0 to 10 in unit increments. A small tilted triangle upper A upper B upper C is formed by connecting the following plots: point upper A is left parenthesis 2 comma 1 right parenthesis; point upper B is left parenthesis 3 comma 2 right parenthesis; and point upper C is left parenthesis 1 comma 3 right parenthesis. A large tilted dotted triangle is formed by connecting the following plots: point upper A prime is left parenthesis 6 comma 3 right parenthesis; point upper B prime is left parenthesis 9 comma 6 right parenthesis; point upper C prime is left parenthesis 3 comma 9 right parenthesis.
What is the scale factor of a single dilation between the preimage ABC and image A′B′C′ ?
1 answer
First, let's find the side lengths of the preimage ABC:
Side AB: sqrt((3-2)^2+(2-1)^2) = sqrt(2^2+1^2) = sqrt(4+1) = sqrt(5)
Side BC: sqrt((1-3)^2+(3-2)^2) = sqrt((-2)^2+1^2) = sqrt(4+1) = sqrt(5)
Side AC: sqrt((3-1)^2+(2-3)^2) = sqrt(2^2+(-1)^2) = sqrt(4+1) = sqrt(5)
Now let's find the side lengths of the image A'B'C':
Side A'B': sqrt((9-6)^2+(6-3)^2) = sqrt(3^2+3^2) = sqrt(9+9) = sqrt(18) = 3*sqrt(2)
Side B'C': sqrt((3-9)^2+(9-6)^2) = sqrt((-6)^2+3^2) = sqrt(36+9) = sqrt(45) = 3*sqrt(5)
Side A'C': sqrt((6-3)^2+(3-9)^2) = sqrt(3^2+(-6)^2) = sqrt(9+36) = sqrt(45) = 3*sqrt(5)
Thus, the scale factor of the dilation is 3.