Suppose each matchstick has length 1 inch. Using 12 such matchsticks, form a figure with area 4 square inches.
6a. In triangle ABC, draw through A a line perpendicular to BC. Choose any point M on this line. Prove: MB² − MC² = AB² − AC².
6b. In triangle ABC, suppose a point M in the plane satisfies MB² − MC² = AB² − AC². Prove that AM ⟂ BC.
Sign in or create an account to reveal answers, view the solution, and save your progress. Create a free account to unlock practice and keep track of your work.
One puzzle per day. Cryptarithm, Magic Square, Summit. No sign-up required to play.
Play daily puzzle →Interactive problems and curated lessons—water pouring, magic squares, knight's tour, and more.
Browse library →See how you rank. Top solvers by problems solved correctly. Sign in to climb the ranks.
View leaderboard →