How To Determine The Lengths Of Each Axis Of An Ellipse When The Length Of 𝑏 B Is Twice Longer Than 𝑎 A And The Area Is Given

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Step 1: Unveil the Formula

The formula for the area (\(A\)) of an ellipse with semi-major axis (\(a\)) and semi-minor axis (\(b\)) lengths is:


\[ A = \pi a b \]


Step 2: Setting the Stage

Let's embark on an example. Suppose we have an ellipse where \(b\) is twice the length of \(a\).


Step 3: Defining Axes Relationship

Given that \(b\) is twice \(a\), we express it as:


\[ b = 2a \]


Step 4: Bridging to the Formula

With \(b = 2a\), we substitute into the area formula:


\[ A = \pi a (2a) \]


Step 5: Solving for \(a\)

\[ A = 2\pi a^2 \]


Solve for \(a\):


\[ a^2 = \frac{A}{2\pi} \]


\[ a = \sqrt{\frac{A}{2\pi}} \]


Step 6: Computing \(b\)

Now, we determine \(b\) using the relationship \(b = 2a\):


\[ b = 2 \times \sqrt{\frac{A}{2\pi}} \]


Step 7: Final Calculation

Let's calculate a concrete example. Say the area \(A\) of the ellipse is 50 square units.


\[ a = \sqrt{\frac{50}{2\pi}} \]


\[ a \approx \sqrt{\frac{25}{\pi}} \]


\[ a \approx 2.8209 \, \text{units} \]


Now for \(b\):


\[ b = 2 \times 2.8209 \]


\[ b \approx 5.6419 \, \text{units} \]

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