SOLUTION: in a circle whose diameter is 20 inches, a chord is 6 inches from the center. what is the length of the cord?

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Question 192963: in a circle whose diameter is 20 inches, a chord is 6 inches from the center. what is the length of the cord?
Found 2 solutions by jim_thompson5910, RAY100:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
First, draw a picture





From the diagram, we see that half of the length of the chord "x" is a leg of a triangle with another leg of 6 units and a hypotenuse of 10 units.


Since we can see that the triangle has legs of 6 and x with a hypotenuse of 10, we can use the Pythagorean theorem to find the unknown side.


Pythagorean theorem:

a%5E2%2Bb%5E2=c%5E2 where a and b are the legs of the triangle and c is the hypotenuse



6%5E2%2Bx%5E2=10%5E2 Plug in a=6, b=x, and c=10. Now lets solve for x


36%2Bx%5E2=100 Square each individual term



x%5E2=100-36 Subtract 36 from both sides


x%5E2=64 Combine like terms


sqrt%28x%5E2%29=sqrt%2864%29 Take the square root of both sides. Note: only the positive square root is considered.


x=8 Simplify the square root



Since the length of "x" is half of the length of the chord, this means that 2%2A8=16 is the length of the entire chord.


So the length of the chord is 16 units.

Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
a rough sketch might help
from center of circle draw a horizontal line to circle perimeter
about half way out draw a perpendicular chord.
from center to point on circle that chord intersects draw the last line. This is a radius and the length is 10.
the triangle constructed is a right triangle, since it bisects a chord.
let x be distance from center of the circle to intersection of chord. This is given to be 6
pythagorous is a good tool for rt triangles. In our case one leg is 6, and the hypotenuse is 10.
c^2=a^2+b^2
10^2 =6^2 +b^2
100-36=64=b^2
or b=8
chord total length is 2b, or 16