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Class 10 Maths NCERT Solution -Chapter 10 Circles This article for 10 th  Class Maths we will discuss theorem’s related to the Tangent. Theorem No 2 The lengths of two tangents drawn from an external point to a circle are equal. Proof Given  Circle with center O Point P outside the circle Two tangents from point P, PQ and PR To Prove  PO=PR Let’s join OP, OQ and OR <OQP and <ORP formed are actually right angles, as per the theorem 1, angles between the radii and tangents are right angles. = OQ=OR                                                          (radii of same circle) = OP=OP                                                           (Common) = Triangle OQP=Triangle ORP                      (RHS) = PQ=PR                                                            (Hence proved) Let’s take an alternative method also to solve using the Pythagoras theorem to prove the same. Alternative method (Using Pythagoras theorem) PQ²=OP²-OQ² =OP