Question

Someone Please Help Me. I don't understand how to do this.

Answer 1

[1] The median to the base passes through the top point (0,b) and the bottom point (0,0) since it is going straight down. The slope formula is
$\frac{y_2-y_1}{x_2-x_1}$
So, the slope of the median is (b-0)/(0-0) = b/0. Technically, this is undefined, but let's leave it this way for now.

[2] The base passes through the left point (-a,0) and the right point (a,0). Its slope must be (0-0)/(a-(-a)) = 0.

[3] We now check if the slopes are negative reciprocals. Flipping b/0 over and putting a negative sign gives:
b/0 -> - 0/b = 0
So the slopes are negative reciprocals, which means the lines are perpendicular.