In a circle with a diameter of 50 cm, a chord is drawn 10cm from the origin. How long is the chord?

Answer 1

Draw a diagram.
Let the center of the circle be O
Let the chord intersect the circle at A,B
Draw a radius OC ⊥ AB, intersecting it at D.
Now you have a right triangle ODB such that
OB = 25
OD = 10
half the chord is DB^2 = 25^2 - 10^2
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