How to use this review
This set mixes all ten Part IV chapters together with no chapter labels, followed by a short addendum of extra mixed practice. Fifty-six minutes of ACT Math will not tell you which chapter a question came from, so the first skill being tested is recognition: read the question, name the topic, and only then pick a tool.
Use this quick map as you work. Angle relationships on parallel lines and triangle angle sums come from the angle chapters; two sides with an included angle call for the Law of Cosines, and two angles with a side call for the Law of Sines; similar figures scale lengths by , areas by , and volumes by ; a right triangle with two known sides calls for the Pythagorean theorem; circles split into equations (complete the square), arc length and area (use the fraction of the circle), and theorems (inscribed angles, chords, secants, tangents); coordinate questions use the distance formula, the midpoint formula, slopes (perpendicular slopes are negative reciprocals), and the rules for reflections, rotations, translations, and dilations; and logic questions ask for converses, contrapositives, counterexamples, or constructions.
No calculator is required, though Desmos or a handheld may still help on a few. After you finish, read every explanation, including those for questions you got right, and note which chapter each missed question belongs to so you can return to that chapter's lesson.