9a-3(a-6)=-6
9a-3a+18=-6
6a+18=-6
6a=-24
a=-4
If they are perpendicular, they form a right angle. For example, this is perpendicular:
I_
If likes are parallel, they run along each other, never meeting. For example, these two lines are parallel:
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Hope this helps!
Answer:
Length of side of square
Step-by-step explanation:
Sides of rectangle
let
be diagonal of rectangle
<u><em>Pythagorean theorem : The square of hypotenuse is equal to sum of square of sides.</em></u>
Here hypotenuse 

Diagonal of square 
let side of square
again use pythagorean theorem
