SOLUTION: A square of side length S and an equilateral triangle of side length S are placed inside a rectangle of length 2S and width S as shown. What fraction of the area of the rectangle

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Question 1061957: A square of side length S and an equilateral triangle of side length S are placed inside a rectangle of
length 2S and width S as shown. What fraction of the area of the rectangle remains uncovered?
Image is in the link: http://prntscr.com/dkzrut

Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
How high is the equilateral triangle?
Base is S and the length of the other two of its sides also S each. Pythagorean Theorem formula will help; imagine cutting the triangle into two parts along the altitude.

S%5E2=%28%281%2F2%29S%29%5E2%2Ba%5E2, using "a" for the altitude length.
a%5E2=S%5E2-S%5E2%2F4
a%5E2=4S%5E2%2F4-S%5E2%2F4
a%5E2=3S%5E2%2F4
highlight_green%28a=S%2Asqrt%283%29%2F2%29


Area of the whole rectangle:
S%2A2S
highlight%282S%5E2%29

Fraction of the area which is uncovered:
%28totalArea-coveredArea%29%2FtotalArea
-
%282S%5E2-%28S%5E2%2B%281%2F2%29S%2Aa%29%29%2F%282S%5E2%29


Substitute for a:

%282S%5E2-%28S%5E2%2B%281%2F2%29S%28S%2F2%29sqrt%283%29%29%29%2F%282S%5E2%29
The simplification algebra steps are not shown here, but final result should be highlight%28%284-sqrt%283%29%29%2F8%29.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
A square of side length S and an equilateral triangle of side length S are placed inside a rectangle of
length 2S and width S as shown. What fraction of the area of the rectangle remains uncovered?
Image is in the link: http://prntscr.com/dkzrut
Area of rectangle: 2S%5E2
Area of square: S%5E2
Area of triangle: %28S%5E2sqrt%283%29%29%2F4
Area uncovered:
Fraction of area uncovered: