Page 25 - Trigonometry

Example 8:

A pattern is made by laying a triangle of length B and
base length A upon a circle whose diameter is D.

Derive an expression for the area of the pattern.

The area of the triangle is,

1

2

To calculate the area of the circle visible, consider the
diagram on the next page. Here the radius has been

marked out (length D/2) and the chord which has a

length A. The angle subtended by the two radii is θ,
and this related to D and A by,

/2
sin ( ) = = 1
2 /2

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