2025 AMC 12B Problem 21

In this video, we discussed 2025 AMC 12B #21 ------------------------------------------------------------------------------------------------------------------------------------- Mastering AMC 10/12 book: https://www.omegalearn.org/mastering-.... The book includes video lectures for every topic on the AMC 10/12 contests, along with many useful formulas and hundreds of examples and practice problems with detailed video solutions. Mastering AMC 8 book: https://www.omegalearn.org/mastering-... The book covers the most important concepts on the AMC 8 contest, and includes video lectures for every chapter, formulas for every topic, and hundreds of examples and practice problems with detailed video solutions. Join our Discord server to discuss problems from our books or any help with math competitions in general: https://bit.ly/OmegaLearnDiscord ------------------------------------------------------------------------------------------------------------------------------------- To get notifications for new videos, click here to subscribe: http://bit.ly/2JjEDqr For more practice, watch the following free courses: 1. AMC 8 Fundamentals Course:    • AMC 8 Fundamentals Course   2. AMC 8 Advanced Course:    • AMC 8 Advanced Course   3. Mastering AMC 8 Course:    • Mastering AMC 8 Course   4. AMC 10/12 Fundamentals Course:    • AMC 10/12 Fundamentals Course   5. Mastering AMC 10/12 Course:    • Mastering AMC 10/12 Course   More resources available at: https://www.omegalearn.org/ ------------------------------------------------------------------------------------------------------------------------------------- Tags: AMC 8, AMC 8 Preparation, AMC 8 Crash Course, AMC 8 Concepts, AMC 8 Review, AMC 10, AMC 12, MATHCOUNTS, MathLeague, Number Theory, Primes, Factors, Competition math, Number of Factors, Sum of Factors, Product of Factors, Permutations, Combinations, Combinatorics, Modular Arithmetic, Recursion, Probability, Divisibility, Competition Math, Area of a Triangle, Similar Triangles, Cyclic Quadrilateral, Power of a Point, 3D Geo, Polygons, Coordinate Geometry