ACT Math · Area and volume

A regular hexagon has side length 6. Which value is closest to its area? (Area of a regular hexagon = 3√(3)2s²)

A regular hexagon has side length 6. Which value is closest to its area? (Area of a regular hexagon = 332s2\frac{3\sqrt{3}}{2}s^2)

Answer and explanation

Answer: D: 94

Substitute s=6s=6 into the formula: A=332(62)=332(36)=543A=\frac{3\sqrt3}{2}(6^2)=\frac{3\sqrt3}{2}(36)=54\sqrt3. Since 3≈1.732\sqrt3\approx1.732, the area is 54(1.732)≈93.554(1.732)\approx93.5, closest to 9494, choice D. Choice B (187187) is double that value. Choice A (6262) is two thirds of the correct value. Choice C (108108) is 3⋅363\cdot36, which uses s2s^2 but leaves out the factor 32\frac{\sqrt3}{2}. A check: a regular hexagon is six equilateral triangles, each of area 34(36)≈15.6\frac{\sqrt3}{4}(36)\approx15.6, and 6(15.6)≈93.56(15.6)\approx93.5. Using the exact value 54354\sqrt{3} avoids rounding errors until the last step.

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