When rotating a figure 270^(∘) counterclockwise about the origin, the coordinates of the image's endpoints will change in the following way.
(a,b)→ (b,- a)
Correct answer: C(1,1) and D(3,- 2). Explanation: See solution.
Practice makes perfect
When rotating a figure 270^(∘) counterclockwise about the origin, the coordinates of the image's endpoints will change in the following way.
(a,b)→ (b,- a)
Using this rule on the endpoints of CD, we can find the endpoints of C'D',
Point
(a,b)
(b,- a)
C
(- 1,1)
(1,1)
D
(2,3)
(3,- 2)
The endpoints of C'D' should be as follows.
C(1,1) and D(3,- 2)
What error was committed? Well, if we look at the calculated coordinates of C' and D', we see that the y-coordinates change their signs. In other words, the following rule was applied.
(a,b)→ (a,- b)
This shows a reflection in the x-axis.
