Question

Point Y (-1,-3) is rotated 180° about the origin. What are the coordinates of its image, point Y prime ?

Answer 1

Refer to the figure shown below.

When the point Y (-1,-3) is rotated 180 about O, it sweeps a semicircular arc to the point Y' (1,3).
The radius of the semicircle is
$r = \sqrt{1^{2} + 3^{2}} = \sqrt{10} \\ or \\ r = \sqrt{(-1)^{2} + (-3)^{2} } = \sqrt{10}$

Answer: 3. Y' (1,3)

Answer 2

The correct answer is (1,3)