To find the radius of the circle from the equation \( x^2 + y^2 - 14x - 4y = 11 \), we will first rewrite the equation by completing the square for both the \( x \) and \( y \) terms.
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Start with the original equation:
\[ x^2 + y^2 - 14x - 4y = 11 \]
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Rearrange the equation:
\[ x^2 - 14x + y^2 - 4y = 11 \]
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Complete the square for the \( x \) terms:
- Take the coefficient of \( x \) (which is -14), divide by 2 to get -7, and then square it to get 49.
- Add and subtract 49:
\[ (x^2 - 14x + 49) - 49 \]
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Complete the square for the \( y \) terms:
- Take the coefficient of \( y \) (which is -4), divide by 2 to get -2, and then square it to get 4.
- Add and subtract 4:
\[ (y^2 - 4y + 4) - 4 \]
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Now rewrite the equation with both squares completed:
\[ (x - 7)^2 - 49 + (y - 2)^2 - 4 = 11 \]
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Simplify this equation:
\[ (x - 7)^2 + (y - 2)^2 - 53 = 11 \]
\[ (x - 7)^2 + (y - 2)^2 = 64 \]
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The equation \((x - 7)^2 + (y - 2)^2 = 64\) is in the standard form of a circle \((x - h)^2 + (y - k)^2 = r^2\), where \((h, k)\) is the center and \(r\) is the radius.
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From our equation, we see:
\[ r^2 = 64 \]
Taking the square root to find the radius:
\[ r = \sqrt{64} = 8 \]
Therefore, the radius of the circle is \( \boxed{8} \).