Which describes how triangle FGH could be transformed to triangle F prime G prime H prime in two steps? On a coordinate plane, t
riangle F G H has points (negative 2, 1), (negative 3, 3), (0, 1). Triangle F prime G prime H prime has points (negative 8, negative 4), (negative 12, negative 12), (0, negative 4). Which identifies the transformation that occurred after the dilation? a dilation by a scale factor of 3 and then a reflection across the x-axis a dilation by a scale factor of 3 and then a 180 degrees rotation about the origin a dilation by a scale factor of 4 and then a reflection across the x-axis a dilation by a scale factor of 4 and then a 180 degrees rotation about the origin
<u><em>A dilation by a scale factor of 4 and then a reflection across the x-axis </em></u>
Explanation:
<u>1. Vertices of triangle FGH:</u>
F: (-2,1)
G: (-3,3)
H: (0,1)
<u>2. Vertices of triangle F'G'H':</u>
F': (-8,-4)
G': (-12,-12)
H': (0, -4)
<u>3. Solution:</u>
Look at the coordinates of the point H and H': to transform (0,1) to (0,-4) you can muliply each coordinate by 4 and then change the y-coordinate from 4 to -4. That is<em> a dilation by a scale factor of 4 and a reflection across the x-axis.</em> This is the proof:
Rule for a dilation by a scale factor of 4: (x,y) → 4(x,y)
(0,1) → 4(0,1) = (0,4)
Rule for a reflection across the x-axis:{ (x,y) → (x, -y)
(0,4) → (0,-4)
Verfiy the transformations of the other vertices with the same rule:
Dilation by a scale factor of 4: multiply each coordinate by 4
4(-2,1) → (-8,4)
4(-3,3) → (-12,12)
Relfection across the x-axis: keep the x-coordinate and negate the y-coordinate
(-8,4) → (-8,-4) ⇒ F'
(-12,12) → (-12,-12) ⇒ G'
Therefore, the three points follow the rules for <em>a dilation by a scale factor of 4 and then a reflection across the x-axis.</em>
