In figure , CA and CB are tangents
to the circle. Also PA=PB and
Answers
Answer:
ohhh same question I was gonna ask this same too xD
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Consider the given figure( attachment)
The lengths of two tangents drawn from an external point to a circle are equal.
Thus, CA=CB
Consider △ABC,
Since,
CA=CB,△ABC is an isosceles triangle.
Thus, the base angles, ∠CAB=∠CBA
★By angle sum property
we have,
m∠CAB+∠CBA+∠ACB=180∘
⇒m∠CAB+m∠CAB+m∠ACB=180∘
⇒2m∠CAB=40∘=180∘
⇒2m∠CAB=140∘⇒m∠CAB=70∘=m∠CBA
Let O be the centre of the circle and OB be the radius.
A tangent to a circle is perpendicular to the radius through the point of contact.
⇒OB⊥CB and OA⊥CA
⇒m∠OBC=90∘ and m∠OAC=90∘
Consider angles, ∠OBA and ∠OAB
m∠OBA=m∠OBC−m∠CBA=90∘−70∘=20∘
Similarly, m∠OAB=m∠OAC−m∠CAB=90∘−70∘=20∘
Consider △AOB,
Since OA and OB are radii, OA=OB
⇒△AOB is an isosceles triangle,
★By angle sum property
we have,
m∠OBA+m∠OAB+m∠AOB=180∘
⇒20∘+20∘+m∠AOB=180∘⇒AOB=140∘
The angle subtended by an arc of a circle at the centre is twice the measure of the angle subtended by it at any point on the remaining part of the circle.
m∠=140∘⇒m∠APB=70∘
Also, given that PA=PB,△APB is an isosceles triangle.
⇒anglePBA=∠PAB
★By angle sum property
we have,
m∠APB+m∠PBA+m∠PAB=180∘⇒70∘+m∠PBA+m∠PBA=180∘
⇒70∘+2m∠PBA=180∘⇒2m∠PBA=110∘⇒m∠PBA=55∘=m∠PAB
Thus, the angles of △APB are m∠PAB=55∘,m∠PBA=55∘,m∠PBA=55∘ and m∠APB=70∘
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