McGraw Hill Glencoe Geometry, 2012
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McGraw Hill Glencoe Geometry, 2012 View details
1. Ratios and Proportions
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Exercise 39 Page 465

Practice makes perfect
a To determine if either type of screen is a golden rectangle, we should simplify the fractions corresponding to the given ratios. Let's start with a standard television screen.

4:3=4/3=1.3333... As we can see, this type of screen is not a golden rectangle because 1.333...≠1.618. Now, let's do the same with a high-definition screen. 16:9=16/9=1.7777... Since 1.777...≠1.618, this type of screen is also not a golden rectangle. Therefore, neither of them can be named a golden rectangle.

b In this part we are asked to find the width of two columns when we are given the width of the page, 960 pixels. Notice that if x is the width of the left column, then 960- x is the width of the right column. As we know that the ratio of these widths is the golden ratio, 1.618, we can write an equation.
x/960- x=1.618Let's solve the above equation for x.
x/960-x=1.618
Solve for x
x=1.618(960-x)
x=1553.28-1.618x
2.618x=1553.28
x=593.307...
x≈593
The width of the left column is approximately 593 pixels. By subtracting x=593 from 960, we can find the width of the right column.
960-x
960- 593
367
The width of the right column is approximately 367 pixels. Notice that this value is also an approximation as we used an approximate value to find it.