trigonometry of right triangle, right-angled triangle trigonometry, the Pythagorean theorem, proofs of the Pythagorean theorem, trigonometric functions of an acute angle defined in a right triangle, solving the right triangle, solving right triangles examples, Pythagorean triple or Pythagorean numbers, applications of the right triangle, examples, oblique triangle, the sine law (rule) or law of sines congruence, the sine law, applications of sine law examples, the cosine law (rule) or law of cosines, calculating angles of triangle, applications of cosine law examples, solving oblique...