Scale MDI child to parent

I'm working on a MDI program for a data editor that I'm designing, similiar to The Elder Scrolls Construction Set. I have the main form, which is the MDI parent, set to be maximized by default. I want to make the children scale themselves to the parent, so that if I run this program on different resolutions the children will keep their same ratio to the Parent. Say I have a child form that takes up half the width and all the height of the parent. I tried setting the Width and Height variables to equal several different size variables of the parent, but none of them give me the correct result.

Code:

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                        EntityEditor.Width = this.MaximizedBounds.Width/2;
                        EntityEditor.Height = this.MaximizedBounds.Height;

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That's just one of the attempts I've made, I tried using just Width and Height, I've tried MaximumSize.Width and MaximumSize.Height, I tried a few others too, and none of the do it correctly. I even swapped MaximizedBounds.Width and MaximizedBound.Height and I got the same result as if I did them to their respectice order.