A dodecagon

Find the surface area of a regular 12-sided polygon if its side is a = 12 cm.

Correct answer:

S =  1612.2459 cm2

Step-by-step explanation:

a=12 cm n=12  α=360/n=360/12=30  β=α/2=30/2=15  tan β =  ha/2  h=tan(β)a/2=tan(15°)12/222.3923 cm  S1=2h a=222.3923 12134.3538 m2 S=n S1=12 134.3538=1612.2459 cm2



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planimetricsgoniometry and trigonometryUnits of physical quantitiesGrade of the word problem

 
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