A = 4


=

r =

I don't see an option for my answer, but this should be right..
Hope this helped though!
When converting English phrases into mathematical expressions/equations, we do things from left to right. That is why it's 4 - 20 instead of 20 - 4.
This rule is applied to division as well.
No. A square has equal sides that are perpendicular and parallel. I'm guessing this room resembles some other figure.
Never,because obtuse angle is an angle measuring between 90 and 180
and if an angle measures 180 then it is a straight angle