Question

Triangle QRS has coordinates Q(–12,10), R(–8,8), S(–1,9). Give the coordinates of each vertex of the image after triangle QRS is dilated by a scale factor of 2.

Q’( , ) R’( , ) S’( , ).

Answer 1

Q' = (-24, 20), R' = (-16, 16), and S' = (-2, 18).

Explanation:

Recall that if a figure is dilated by a scale factor k (about the origin), then its coordinates become:

`(x, y) \rightarrow (kx, ky)`

In other words, we simply multiply each coordinate by the scale factor.

Triangle QRS with coordinates Q(-12, 10), R(-8, 8), and S(-1, 9) is dilated by a scale factor of two.

And we want to determine the coordinates of Triangle Q'R'S'.

Multiply each coordinate by the scale factor (two). Hence:

Q' = (-24, 20),

R' = (-16, 16), and

S' = (-2, 18).

Note: This method is only true when the figure is dilated about the origin.