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feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

No trig or anything real advanced needed here. Merely that the square of the hypotenuse of a right triangle = the sum of the squares of the other two sides

Picture your arc, and a line between the ends of the arc. Now draw another line from the center of your circle to the midpoint of the arc, and a third line from the circle center to one of the endpoints. Now if you have a circle of radius R, you have just drawn a right triangle with hypotenuse R, one side of R-2, and the other side of 30 (converting the 5-ft width to inches and dividing by 2.

30^2 + (R-2)^2 = R^2

900 + R^2 -4R + 4 = R^2

904 = 4R

R"6"

#### Site Timeline

- posted on April 16, 2013, 3:23 am

feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

No trig or anything real advanced needed here. Merely that the square of the hypotenuse of a right triangle = the sum of the squares of the other two sides

Picture your arc, and a line between the ends of the arc. Now draw another line from the center of your circle to the midpoint of the arc, and a third line from the circle center to one of the endpoints. Now if you have a circle of radius R, you have just drawn a right triangle with hypotenuse R, one side of R-2, and the other side of 30 (converting the 5-ft width to inches and dividing by 2.

30^2 + (R-2)^2 = R^2

900 + R^2 -4R + 4 = R^2

904 = 4R

R"6"

--

Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

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