# Substitute ME!

Geometry Level pending

The two sides of a triangle measures 18 and 14 units with an angle of $$10.84^0$$. Evaluate sin $$\frac{π}{a}$$ - sin $$\frac{2π}{a}$$ - sin $$\frac{3π}{a}$$ - . . . - sin $$\frac{8π}{a}$$ + sin $$\frac{9π}{a}$$, if a is equal to the third side of the triangle.

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