1. Overview of Angles & Triangles.
Angles & Trigonometry.
Overview of Angles & Triangles.

2. Angles & Trigonometry. Three types of angles you should know include-
Acute Angle – less than 90º
Obtuse Angle – more than 90º less than 180º
Reflex Angle – Between 180º & 360º.

3. Angles & Trigonometry.
Common workshop calculations relating to angles include Trigonometry.
‘Trig’ is used to perform calc’s of triangles to discover angles and lengths.
The sides of triangles are given special names –
Hypotenuse
Opposite
Adjacent.

4. Angles & Trigonometry.
The right angled triangle displays the terms given to sides.

5. Angles & Trigonometry.
There are three formulae involved in trigonometry –
sine = opposite/hypotenuse
Cosine = adjacent/hypotenuse
tangent = opposite/adjacent

6. Angles & Trigonometry. Find the length of side BC.
We are given angle A and side AB. AB is the hypotenuse. BC is opposite angle A. Therefore we use the formula:
sin = opposite/hypotenuse

7. Angles & Trigonometry.
sin 30 = BC/7 Multiply both sides by 7: 7 x sin 30 = BC BC = 3.5cm
*sin 30º = 0.5

8. Angles & Trigonometry. Find angle C.
AC is adjacent to angle C. BC is the hypotenuse. We therefore use the formula:
cos = adjacent/hypotenuse

9. Angles & Trigonometry.
cos C = 5 ÷ 7 To calculate C, we need to find the inverse of cos (INV cos or SHIFT cos): 5 ÷ 7
Inv cos = 44.4°