Question

A triangle with vertices at (0, 4), (3, 5), and (2, −1) is rotated 90° counterclockwise about the origin. What are the vertices of the image?

Answer 1

@ZeHanz @zepdrix

Answer 2

@best_mathematician

Answer 3

Make a drawing. Do the rotation with (3, 5). See where it arrives.
Do the same with (2, -1). Then you will be ready to come up with a conjecture that involves the new position of points rotated counterclockwise about the origin :)

Answer 4

im having a hard time understanding it... what do you mean rotate it ?

Answer 5

rotation matrix:
\[\left[\begin{matrix}\cos\theta&-\sin\theta\\\sin\theta&\cos\theta\end{matrix}\right]\]
you just have to multiply each co-ordinate with this matrix and you get your rotated co-ordinates.
do you need the theory behind it?

Answer 6

yes I need all the help I can get with this one im so confused

Answer 7

your original point in space

Answer 8

rotation by theta in counter clockwiges gave a new point P'