Question

https://s12.postimg.org/oesbhkifx/image.jpg can someone please explain how to rotate this 90 degrees in simple terms, thankyou

Answer 1

for example when you have a point Q(3,4), and you have to rotate it 90 degree anti-clockwise.
according to the photo I attached, point A lies on the first quarter, (x,y), and when you rotate it 90degree anti-clockwise, you'll get (-y,x), which is (-4,3).
The key is (x,y)----> (-y,x)
The question is easy, try it !! ;)

Answer 2

thanks!