Which is not a property of all similar triangles

Me! #1 write an equation for the interior angles of this triangle that uses the triangle sum theorem. #2 what is the value of x? #3 what is the measure of #4 classify the triangle above as acute, obtuse, or right. state your reason in a complete sentence.

Find the area of the triangle formed by the origin and the points of intersection of parabolas y=−3x^2+20 and y=x^2−16.

Aquadrilateral has exactly 3 congruent sides davis claims that the figure must be a rectangle why is his claim incorrect.