By the solution of right triangles is meant the finding of unknown sides or angles when values of other sides and angles are known.

Example 1

Given A = 30 degrees, c = 24; Find B, a, b.

Solution - B=90 - 30 = 60 degrees. (The sum of the angles of a triangle equals 180 degrees. C = 90 degrees.) a/c=sin A; whence, a = c sin A. (a=c times sine .4.)

(2) A U A A a/c =cos A; whence b = c cos A. c

From the Tables, Appendix II, sin of A, or 30 degrees, = .5. Substituting numerical values in (1), a=12.

Again, from Tables, cos A, or 30 degrees, = .866. Substituting numerical values in (2), 6 = 20.784.

Arith. check - c2 = a2+b2; 242=122+20.782; 576=144+431.8; 576 = 576.