Trigonometrical Ratios

This item is taken from IGCSE Mathematics (0580) Paper 12 of May/June 2014.


To deal with this item, let us summarize the details of the problem:
   (a) Syllabus area: Trigonometry
   (b) Specific topic: Trigonometrical Ratios
   (c) Formula Needed:
To easily remember the trigonometrical ratios, take note of SOH - CAH - TOA.

Let us start to identify the given angle and the given sides.Furthermore, identify the relation of the given sides to the given angle.

Now, let us identify which of the trigonometrical ratios is applicable. First, side AB is adjacent to the given angle and AC is the hypotenuse. This leads us to use cosine.

Simplifying and finding the length of AB.

Therefore, the length of AB is 7.06 cm.

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