Circles: Products of Secants
For secants intersecting a circle, the product of entire secant length times the length corresponding to its interior porition will be the same for each secant.
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In the figure above, the product for segment of each chord equal 24:
Find the length of the chord, x, in the illustration below:
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Solution:
x = 16
- First Secant: (3 + 5)(3) = (8)(3) = 24
- Second Secant: (2 + 10)(2) = (12)(2) = 24
Example:
Find the length of the chord, x, in the illustration below:
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Solution:
The chord, x, corresponds to the inner portion of the bottom secant.
Using products of secants, it follows that:
(3)(3 + 9) = 2(2 + x)
(3)(12) = 4 + 2x
36 = 4 + 2x
32 = 2x
Using products of secants, it follows that:
(3)(3 + 9) = 2(2 + x)
(3)(12) = 4 + 2x
36 = 4 + 2x
32 = 2x
x = 16
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