I need help with this question​

Write a function for a rotation 90 degrees counter clockwise about the origin, point 0

Cody was 165cm tall on the first day of school this year, which was 10% taller than he was on the first day of school last year.

Point r divides in the ratio 1 : 5. if the coordinates of e and f are (4, 8) and (11, 4), respectively, what are the coordinates of r to two decimal places?