# Need to find the radius Any assistance much appreciated. Note by Monty McGee
3 years, 2 months ago

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sqrt [ r^2 - (r-1)^2 ] + r = 5;

r = 6 +/- sqrt(10);

r = 6 - sqrt(10);

r = 2.84

- 3 years, 1 month ago

The drawing is not correct; I didn't draw it correctly with the Word drawing tool; it is supposed to be a circle.

- 3 years, 2 months ago

I don't think there is enough info to solve the problem. That's not a circle, it's an oval. It's wider than it is tall. It won't have 1 radius.

- 3 years, 2 months ago

- 3 years, 2 months ago

Hi Annie. Thanks for the comment. Who is Siri ?

- 3 years, 2 months ago

Oh know, the apple help system. Here is some information about it: Siri

- 3 years, 2 months ago

Thanks.

- 3 years, 2 months ago

No probs. Just remember to thank Siri

- 3 years, 2 months ago

Hint 1: Try forming a right triangle.

Hint 2: Let $O$ be the center of the circle and $X$ be the point where the rectangle touches the circle. Create a right triangle with $OX$ as the hypotenuse and whose side lengths you can easily find.

- 3 years, 2 months ago

You are assuming that rectangle touches the circle, when the illustration shows that it doesn't.

- 3 years, 2 months ago

That's my fault; I didn't draw it correctly. The rectangle is indeed supposed to be touching the circle.

- 3 years, 2 months ago

Thanks, Steven. I tried that before but obviously did not hit upon the correct setup; will go at it again.

Monty

- 3 years, 2 months ago

Have tried in vain to find the radius.

- 3 years, 2 months ago