Draw a triangle that has degrees of 30, 60, and 90. Measure the side lengths.

Angle 1 = 30°
Angle 2 = 90°
⇒ Angle 3 = 60°
So, it's right triangle. We can set the length of one side and get all other sides.
So, we have 1 triangle. If there are 2 or more triangles with the same data, all the triangles will be congruent because of : Two triangles are congruent if "ASA: Two interior angles and the included side in a triangle have the same measure and length, respectively, as those in the other triangle."

(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