Question

Which of the following describes the rotation shown ? 4 T 2 U -4 2 4 U S 2 T is a 90 rotation about the origin of ASTU AST'U a 180 rotation about the origin of ASTU ASTU a 270 rotation about the of ASTU a rotation about the origin ASTU

Answer 1

To answer this question, we need to remember that:

That is, we have to multiply by -1 each of the coordinates of the preimage to get the image.

We can check this if we identify the coordinates of the vertices of the triangle which is the preimage:

• S(-4, 2)

,

• T(-1, 3)

,

• U(-2, 1)

Therefore, to obtain the image for a rotation of 180° about the origin, we have:

• S(-4, 2) ---> (-(-4), -2) ---> S'(4, -2)

,

• T(-1, 3) ---> (-(-1), -3) ---> T'(1, -3)

,

• U(-2, 1) ---> (-(-2), -1) ---> U'(2, -1)

Hence, the coordinates of the vertices of the image are:

• S'(4, -2)

,

• T'(1, -3)

,

• U'(2, -1)

And we can see that they correspond with the ones in the image of the corresponding graph.

In summary, we can say that ∆S'T'U' is a 180° rotation about the origin of STU (second option).is the preimage:∆