Problem 3.1: Square ABCD has diagonals that intersect at point E. How do you know that triangles AEC and DEB are congruent? [Solution]

Problem 3.2: Quadrilateral ABCD is a rhombus with diagonals that intersect at point E. Given angle ABE = 30 degrees and segment AD = 5, what is the area of triangle EBC? [Solution]

Problem 3.3: What is the relationship between an upper base angle and a lower base angle of an isosceles trapezoid? [Solution]

Problem 3.4: A midsegment connects the midpoints of the legs of an isosceles triangle. What is the most specific name by which the quadrilateral created can be called? [Solution]

Problem 3.5: The endpoints of a segment and a point on the perpendicular bisector of that segment are the three vertices of a triangle. What kind of triangle must it be? [Solution]