<PRE><B>Question 1148864</B>
One square is placed on top of another so that a regular octagon is formed, along with eight isosceles triangles each with its hypotenuse on a side of the octagon. If the perimeter of the octagon is 20cm, find the perimeter of the star, in cm.
:
Find the length of each side (c) of the octagon
c = {{{20/8}}}
c = 2.5 cm, is the hypotenuse of the 8 triangles
Find the length of the sides (a) of the 8 triangles 
2a^2 = 2.5^2
2a^2 = 6.25
a^2 = {{{6.25/2}}}
a = {{{sqrt(6.25/2)}}}
the 16 sides of the star
perimeter = {{{16*sqrt(6.25/2)}}} = 28.284 cm
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