Question

What is the image of the point (-1,-2)after a rotation of 180∘

counterclockwise about the origin?

Answer 1

(1,2)

Explanation:

Answer 2

The image of the point is (1, 2)

Explanation:

• If the point (x, y) rotated about the origin by angle 90° counterclockwise, then its image is (-y, x)

• If the point (x, y) rotated about the origin by angle 180° counterclockwise, then its image is (-x, -y)

• If the point (x, y) rotated about the origin by angle 270° counterclockwise, then its image is (y, -x)

Let us use the rules above to solve the question

∵ The point (-1, -2) is rotated 180° counterclockwise about the origin

→ By using the 2nd rule above change the signs of x and y coordinates

∴ Its image is (1, 2)

∴ The image of the point is (1, 2)