How do we know when to do the opposite reciprocal?

The corner of a rectangle is 90 degrees.  Therefore AB will be perpendicular to AD.

Step-by-step explanation:

Since those two lines are perpendicular, their slopes will be opposite reciprocals of each other.  So to find AB, first find AD, then take the opposite reciprocal of that slope.

step-by-step explanation:

if you want to separate 54 into 6 individual tiers then you need to divide if you want to separate 54 into 6 individual tiers then you need to divide 6 and 54.

if you divide 9 by 6 you will get 54.

- hope i .