Exercise 1: Solving a New Triangulation Problem With the Law of Sines — Possible Solution ==================================================================== FINDING THE THIRD ANGLE ------------------------------ Baseline AB = 200m, angle at A = 50 degrees, angle at B = 65 degrees. The third angle, at the landmark (call it T), is found the same way this chapter's own worked example found it: angle T = 180 - 50 - 65 = 65 degrees COMPUTING THE TWO DISTANCES ------------------------------ Using the Law of Sines exactly as this chapter's own worked example did, AT/sin(B) = AB/sin(T) = BT/sin(A): AT = AB * sin(B) / sin(T) = 200 * sin(65) / sin(65) = 200.0m BT = AB * sin(A) / sin(T) = 200 * sin(50) / sin(65) = 169.05m (computed precisely: AT = 199.99999999999997, matching 200 to floating-point precision; BT = 169.04730469627978) WHY AT CAME OUT EQUAL TO THE BASELINE ITSELF ------------------------------ This isn't a coincidence or an error - it happens because angle B (65 degrees) and angle T (65 degrees) are equal. Whenever two angles of a triangle are equal, the sides opposite them are also equal (the triangle is isosceles) - here, the side opposite angle B is AT, and the side opposite angle T is AB. Since angle B = angle T, AT must equal AB, which is exactly what the Law of Sines calculation confirmed (up to a tiny floating-point rounding difference in the last digit). This is a good, self-checking property: getting a result that matches a known geometric fact (equal angles imply equal opposite sides) here is a useful independent confirmation that the calculation was set up correctly. WHY THIS WORKS AS AN ANSWER ------------------------------ The answer applies the Law of Sines correctly to compute both distances, and additionally notices and explains the geometric reason AT came out equal to the baseline itself (the isosceles-triangle property from the coincidentally equal angles), which serves as a built-in sanity check on the arithmetic rather than treating the matching values as an unremarked coincidence.