Tangents #1
Geometry
Level
1
Two equal and parallel chords of a circle are tangents to a smaller circle(concentric with the greater one). If lengths of chords are 24 cm each and distance between them is 10 cm, find radius of larger circle.
15
12
13
10
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1 solution
Half of the chord=24/2=12,we know that perpendicular from center on the chord bisects it.And the distance between them is 10 which is the diameter of small circle,so radius of it=10/2=5,now this is the length of the perpendicular,so we have right triangle with 5-12,so other has to be 13,hence the radius of the bigger circle is 13