SOLUTION: Two parallel chords 16 cm and 30 cm long are 23cm apart. What is the radius of the circle?

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Question 82527: Two parallel chords 16 cm and 30 cm long are 23cm apart. What is the radius of the circle?
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the center of the circle lies on the line connecting the midpoints of the chords, this line is also perpendicular to the chords

let x equal the distance from the center to the 30 cm chord, so 23-x equals the distance to the 16 cm chord

a right triangle is formed by x, half of the 30 cm chord and the radius

similarly, another right triangle is formed by 23-x, half of the 16 cm chord and the radius

using Pythagoras, x%5E2%2B15%5E2=r%5E2 and %2823-x%29%5E2%2B8%5E2=r%5E2 ... so x%5E2%2B225=529-46x%2Bx%5E2%2B64 ... 225=593-46x ... x=8

8%5E2%2B15%5E2=r%5E2 ... 289=r%5E2 ... r=17 cm