IKMC 2023 - Grades 9-10 - Self-study Question 23

Question 23

A rectangle has vertices (0,0), (100,0), (100,50), (0,50). A circle centred at (75,30), radius 10, is cut out. What is the gradient of the line through (75,30) that bisects the remaining area?

$1/5$
$1/3$
$1/2$
$2/5$
$2/3$