How do you find the area of the missing side

Lets use a rectangle as the example because I dont know what kind of shape you're looking for.

Area of a rectangle = length * width

Length (l) = 62

Width (w) = x

Area = 744

744 = 62 * x

Divide both sides by 62

744/62 = 12

12 = x

That means the width would equal 12

12 * 62 = 744