Aregular polygon has sides that are perpendicular. what is the measurement of each angle?

They are 90* because perpendicular sides form a right angle hope this helped have a great day!!!

(m+11n)^2=(m+11n)(m+11n)=m^2+11mn+11mn+121n^2=m^2+22mn×121n^2 for example; use foil: (a+b)(a+b)first. a^2outside. abinside. ablast. b^2