Math question: In ΔABC, if AB ≅ DC and ∠ABC ≅ ∠CDA, find the possible value of ∠BCA (in degrees).
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Math question: How many ways can 5 people be arranged in a line if 2 of the people must always stand next to each other?
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Write a math question for the theme "Characteristics of quadratic (square) function f(x) = x^2": What is the vertex form of the quadratic function f(x) = x^2? Provide an example of vertex coordinates and explain how the "a" value affects the graph of the function.