The vertices of a triangle are A(2,3), B(–4,5), and C(2,–1). If the triangle is reflected over the y-axis, what is the area of the resulting triangle?
Correct: A
Reflection does not change area. Use determinant: Area = ½ |(2(5–(–1)) + (–4)(–1–3) + 2(3–5))| = ½ |(12 +16 + (–4))| = ½×24 = 12. Reflected triangle area is same, 12 sq. units.