How do you find the length in feet of the boundary you’re given ?

The parking lot of a store has the shape shown. all angles are right angles. what is the area of the parking lot?

The following division is being performed using multiplication by the reciprocal find the missing numbers is 5/12 divided by x/3 equals 5/12 times x/10 equals 1/x

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /