Parallel-line angle relationships, triangle angle sums, similarity and congruence, and the triangle inequality.
75
Total questions
47
Easy
18
Medium
10
Hard
This skill covers the angle-chasing toolkit: vertical angles, parallel lines cut by a transversal, triangle angle sums, exterior angles, isosceles base angles, and similar triangles with proportional sides. Questions often stack several rules in one figure.
Chase angles systematically: mark every angle you can deduce, one rule at a time, rather than hunting for a single clever step. For similar triangles, set up the proportion by matching corresponding vertices in the similarity statement — the order of the letters tells you exactly which sides pair up.
Straight from the Grind1600 question bank — try each one before revealing the answer.
Correct answer: D
Choice D is correct. The sum of the angle measures of a triangle is 180°. Adding the measures of angles P and Q gives 35° + 85° = 120°. Therefore, the measure of angle R is 180° - 120° = 60°. Choice A is incorrect (may result from a calculation error). Choice B is incorrect (may result from subtracting the measure of angle P from the measure of angle Q: 85° - 35° = 50°). Choice C is incorrect (this is P + Q, not subtracted from 180°).
Correct answer: D
Choice D is correct. If angle C = 85°, then angle D = 180° - 55° - 85° = 40°. The angles would be 55°, 85°, and 40° — no two are equal, so the triangle is not isosceles. Choice A is incorrect (55°, 55°, 70° is isosceles). Choice B is incorrect (55°, 62.5°, 62.5° is isosceles). Choice C is incorrect (55°, 70°, 55° is isosceles).
Area & Volume
Areas of 2D figures and volumes of 3D solids, including composite shapes and problems where scaling changes area or volume.
Right Triangles & Trigonometry
The Pythagorean theorem, special right triangles, and SOH-CAH-TOA trigonometric ratios, including the sine-cosine complement relationship.
Circles
Circle equations in the xy-plane, arc length, sector area, central angles, and completing the square to find center and radius.
75 Lines, Angles & Triangles questions with step-by-step explanations, woven into a day-by-day study plan built for your test date.
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