Question

What are the vertices of the image r(90°, O) (△BCD)?

A. B'(−3, −3), C'(−1, 4), D'(2, 0)
B. B'(3, 3), C'(1, −4), D'(−2, 0)
C. B'(3, −3), C'(1, 4), D'(0, 2)
D. B'(−3, −3), C'(−1, −4), D'(0, −2)

Answer 1

The correct option is;

A. B'(-3, -3), C'(-1, 4), D'(2, 0)

Explanation:

The given coordinates of the vertices triangle ΔBCD, are;

B(-3, 3), C(4, 1), D(0, -2)

The transformation to be performed is r(90°, 0) (ΔBCD) which is a 90 degrees counterclockwise rotation about the origin

The rule for transformation of a geometric figure by rotation of 90 degrees counterclockwise is given as follows;

The coordinates of the preimage (x, y), the coordinates of the image (-y, x)

Therefore, we have;

The preimage B(-3, 3), the coordinates of the image after 90 degrees counterclockwise rotation is B'(-3, -3)

Similarly, we have;

The preimage C(4, 1), the coordinates of the image after 90 degrees counterclockwise rotation is C'(-1, 4)

For the point D, we have;

The preimage D(0, -2), the coordinates of the image after 90 degrees counterclockwise rotation is D'(2, 0)

Therefore, the correct option is B'(-3, -3), C'(-1, 4), D'(2, 0).