In the adjoining figure, if PA and PB are tangents to the circlewith c

1.	In the adjoining figure, if PA and PB are tangents to the circlewith centre O, such that ZAPB 50 Then, find COA
Answer» Since OA is perpendicular to PA and also, OB is perpendicular to PB ∠APB + ∠AOB = 180° 50°+ ∠AOB = 180° ∠AOB = 180° – 50° = 130° In △AOB, OA = OB = radii of same circle ∠OAB = ∠OBA = x ( say ) Again, ∠OAB + ∠OBA + ∠AOB = 180° x +x + 130° = 180° 2x = 180° – 130° = 50° X = 25° Hence, ∠OAB =25°

In the adjoining figure, if PA and PB are tangents to the circlewith centre O, such that ZAPB 50 Then, find COA

Answer»

Since OA is perpendicular to PA and also, OB is perpendicular to PB

∠APB + ∠AOB = 180°

50°+ ∠AOB = 180°

∠AOB = 180° – 50° = 130°

In △AOB,

OA = OB = radii of same circle

∠OAB = ∠OBA = x ( say )

Again, ∠OAB + ∠OBA + ∠AOB = 180°

x +x + 130° = 180°

2x = 180° – 130° = 50°

X = 25°

Hence, ∠OAB =25°