Question

Suppose that the area between a pair of concentric circles is 49pi. Find the length of a chord in the larger circle that is tangent to the smaller circle.

Answers

Steve
Of we call the two circles r and R, and the center O, draw the tangent and let P be where it touches circle r, and Q be where it intersects R.

Then the triangle OPQ is a right triangle with one leg r and the hypotenuse R. The other leg is thus sqrt(R^2-r^2)

But, pi*R^2 - pi*r^2 = 49pi.
So, R^2-r^2 = 49, and the length of the tangent chord is 14.
BOB
Ditto and COPYCAT!
Ankush Vasireddy
That's true
alln
14
AoPS Hackers
L^2=49.
L=7.
2L=14.
Happy to help- AoPS Hackers
a
Aops hacker

sure bud
AoPS
Please do not post HW questions here.
boi
nah nobody care what u saybud
KIWI
reheheheh

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