Advertisements
Advertisements
प्रश्न
In the given figure, O is the centre of two concentric circles of radii 5 cm and 3 cm. From an external point P tangents PA and PB are drawn to these circles. If PA = 12 cm then PB is equal to ______.
पर्याय
`5sqrt(2)` cm
`3sqrt(5)` cm
`4sqrt(10)` cm
`5sqrt(10)` cm
MCQ
रिकाम्या जागा भरा
Advertisements
उत्तर
In the given figure, O is the centre of two concentric circles of radii 5 cm and 3 cm. From an external point P tangents PA and PB are drawn to these circles. If PA = 12 cm then PB is equal to `underlinebb(4sqrt(10) cm)`.
Explanation:
Join OB. Then, OA = 5 cm, OB = 3 cm.
`OP = sqrt(OA^2 + PA^2)`
= `sqrt(5^2 + 12^2)`
= 13 cm
`PB = sqrt(OP^2 - OB^2)`
= `sqrt(13^2 - 3^2)`
= `sqrt(160) cm`
= `4sqrt(10) cm`
shaalaa.com
या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
