In fig. XP and XQ are tangents from X to the circle with center O. R is a point on the circle. Prove that, XA + AR = XB + BR. [2 MARKS]
Concept: 1 Mark
Application: 1 Mark
Since lengths of tangents from an exterior point to a circle are equal.
∴ XP = XQ .... (i) [From X]
AP = AR .... (ii) [From A]
BQ = BR .... (iii) [From B]
Now, XP = XQ
⇒XA+AP=XB+BQ
Using equations (i) and (ii)
⇒XA+AR=XB+BR