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33 votes
a golden rectangle is to be constructed such that the shortest side is 23ft long. How long is the other side? round to the nearest tenth of a foot

User AbbeGijly
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1 Answer

22 votes
22 votes

Answer:

37.2

Step-by-step explanation:

A golden rectangle is a rectangle that satisfies the following proportion:


(a+b)/(a)=(a)/(b)

Where a is the shortest side and (a+b) is the length of the other side. So, we can replace a by 23 and calculate b as:


(23+b)/(23)=(23)/(b)

Applying cross-multiplication, we get:


\begin{gathered} (23+b)\cdot b=23\cdot23 \\ 23b+b^2=529 \\ b^2+23b-529=0 \end{gathered}

Therefore, we can find the solutions to the quadratic function as:


\begin{gathered} b=\frac{-23\pm\sqrt[]{23^2-(4\cdot1\cdot(-529))}_{}}{2\cdot1} \\ b=14.215 \\ or \\ b=-37.215 \end{gathered}

Since -37.215 doesn't have any sense here, the value of b is 14.215

It means that the length of the longest side is:

a + b = 23 + 14.215 = 37.215

So, the answer is 37.2

User SgtFloyd
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3.3k points