1. Review of Essential Skills:
Trigonometry & Proportioning

2. Right Angled Triangle Trigonometry
Sides of a right-angle triangle:
Hypotenuse: Opposite the angle, the longest side in the triangle.
Adjacent: Side, along with the hypotenuse, that “builds” the angle.
Opposite: Side that the angle opens up to.
The adjacent and opposite sides change depending on which acute angle you are referring to.

3. Consider ∆ABC: From A: Adjacent side = c Opposite side = a From C:
Adjacent side = a
Opposite side = c A B C a b c

4. Primary Trig Ratios Or remember: SOH CAH TOA
Ratios that allow us to solve for unknown lengths / angles.
hyp
opp
adj
Or remember: SOH CAH TOA

5. Eg.1: Completely solve ∆ABC where B = 900, a = 5 cm and b = 10 cm.

6. Sine & Cosine Laws
Trig laws that are designed for triangles that are non-right angle.
SINE LAW:
COSINE LAW: A b c C B a

7. Eg.2: Completely solve ∆GHI where g = 8 cm, G = 600 and H = 700.
Eg.3: Completely solve ∆DEF where d = 10 cm, e = 15 cm and f = 17 cm.

8. Proportioning
A solution method which uses comparisons instead of values to determine solutions.
Very useful in situations with many unknowns.

9. Eg. 4: A circle has an area of 10 cm2
Eg.4: A circle has an area of 10 cm2. Determine the area of a circle with a radius that is 25% larger.
Eg.5: The volume of a cone is 50 cm3. Determine the volume of a cone that is 35% taller with a radius that is 25% narrower at the base.