Trigonometric Ratios

Question

1. In each of the following triangles, give the 3 trigonometric ratios for angle a , accurate to 4 decimal places. Then find the size of angle a , accurate to one decimal place. Diagrams are not drawn to scale. (4 marks)

Answer 1

For each triangle, use the trig ratios:

If you have only 2 sides, use the Pythagorean Theorem to solve for the 3rd side, then use that in the ratios above.

Remember that the hypotenuse (hyp) is the side opposite the right angle (always the longest side). The opposite side is the one you would be looking at if you were standing on the angle. The adjacent side is the one right next to the angle that is NOT the hypotenuse.

Example: For triangle a) sin(A) = opp/hyp = 8/10 or reduced = 4/5 or 0.8000