Items 1416 Use the figure to the right 14 Use the coordinate

Items 14-16: Use the figure to the right. 14. Use the coordinate rules to rotate ABC 900 counterclockwise around the origin. List the coordinates and draw the image of A\'B\'C\'. 15. Find the image matrix that results from a 270° counterclockwise rotation of A\'B\'C\' from problem 14. A\' B\' C\" A\" B\" C 16, why you would expect A\"B\"C\" to have the same vertices as ABC from problem, 14?

Solution

Counter clockwise rotation of 90 degree about origin changes the coordinate as (x,y) to (-y,x).

Therefore

(a,b)------(-b,a)

(-1,-2)------(2,-1)

(1,2)-------(-2,1)

(3,-1)-------(1,3)