Hard Geometry Question?

first draw a cirlce then the cord. draw the distance from the chord two the center. now from the center draw a line to the end of the chord. now you have a right traingle with the unkown side being the radius. side a =8(distance from chord to center) b=8 (half of the chord) c= radius

use pathagoreans theroem 8^2+8^2=c^2 i get sq root of 128 which = 11.31

Will seem easier if you make sketch of a circle with a chord.

You know it is 16 cm long so if you mark a midpoint

you can write in 8 cm for each of the half chord lengths.

Join the centre of the circle to the middle of the chord.

We have been told that length is also 8 cm, so mark that in,

and notice that that length is at right angles to the chord.

Join the centre to one of the ends of the chord.

That length is two things.

a) It is the hypotenuse of a right triangle with other sides 8 and 8.

b) It is the length of the radius of the circle.

That should be enough explanation on how find

the radius without actually giving you the answer.

Regards - Ian

Draw a circle, draw a cord on the circle of length 16. draw a perpendicular from the center of the cord to the center of the circle (the length of which is 8). Connect the ends of the cord to the center of the circle to make 2 triangles. The radius is just the hypotenuse of either of these triangles and is 8*sqrt(2)