2000005908 | math4u.vsb.cz

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2000005908

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Easy:

1

Which of the following formulas gives the area of a regular nonagon inscribed in a circle with radius

r

? (See the picture.)

\frac{9 r^{2} \sin 40^{\circ}}{2}

9 r^{2} \sin 40^{\circ}

\frac{9 r^{2} \cos 40^{\circ}}{2}

\frac{9 r^{2} \sin 20^{\circ}}{2}