Trigonometry

Exact trigonometric ratios

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• type the number in to calculator with the appropriate function button
• square that number
• turn it into a fraction

Special right triangles

• two types of special right triangles
• 30-60-90 and 45-45-90
• in a 30-60-90, the length of the longer side is root 3 times the length of the shorter leg
• the length of the hypotenuse is 2 times the length to the shorter side
• in a 45-45-90 , the length of the is root 2 times the length of the leg
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Radians and degrees

• Radians and degrees are two ways of measuring angles.
• The formal definition of a radian is that a radian is the measure of an angle that, when drawn as a central angle of a circle, intercepts an arc whose length is equal to the length of the radius of the circle. The radian measure for a full (360 degree) circle is 2π.
• how to convert - https://www.youtube.com/watch?v=wcfkDuFpbiM
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Angles of elevation and depression

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• The angle of elevation of an object as seen by an observer is the angle between the horizontal and the line from the object to the observer's eye (the line of sight).
• If the object is below the level of the observer, then the angle between the horizontal and the observer's line of sight is called the angle of depression.

Compass bearings

Law of sines