Question

Uuuue radius of the circle.
1. Two concentric circles are of radii 5 cm and 3 cm. Find the length of the chord of the
larger circle which touches the smaller circle​

Answer 1

Explanation:

in above picture O is the center of two concentric circle

OC perpendicular to AB( because AB touches the circle at the point C)

now, OC = 3 cm

OA = OB = 5 cm

so, in tringle OAC ,< OCA = right angle

so, AC =

$\sqrt{ {5}^{2} - {3}^{2} } = \sqrt{25 - 9} = \sqrt{16} = 4 \: cm$

now , AC = CB (we know the a line from the center always bisect any cord if the line is perpendicular)

so, AB = AC + CB = 4 cm +4 cm = 8 cm