Question 370627
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If A, B, and C lie on the circle, O is the center of the circle, and the radius is 10 cm, then OA, OB, OC, AB, and BC must all measure 10 cm because OA, OB, and OC are all radii, and AB and BC are congruent because of congruent sides of a rhombus.


Hence, the area of the rhombus is twice the area of an equilateral triangle with sides that measure 10 cm.


The area of an equilateral triangle of side s is:  *[tex \Large \frac{s^2\sqrt{3}}{4}], hence the area of the rhombus is 


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ A_{rhombus}\ =\ \frac{s^2\sqrt{3}}{2}\ =\ \frac{100\sqrt{3}}{2}\ =\ 50\sqrt{3}\ \approx\ 86.6\text{ cm^2}]


John
*[tex \LARGE e^{i\pi} + 1 = 0]
My calculator said it, I believe it, that settles it
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