1003021603 | math4u.vsb.cz

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Project ID:

1003021603

Source Problem:

Accepted:

1

Clonable:

1

Easy:

0

Which of the following formulas expresses the area of a regular decagon inscribed in a circle of radius

r

? (See the picture.)

10 r^{2} \sin 18^{\circ} \cos 18^{\circ}

10 r^{2} \sin 36^{\circ} \cos 36^{\circ}

5 r^{2} \sin 36^{\circ}

5 r^{2} \sin 18^{\circ}