two circles C1 and c2 touch each other internally at Q with centres O and O' respectively.  radii of bigger and smaller circles are 4 cm and 3 cm respectively and ACDB is the STRAIGHT line of 2√15 cm To Find : lengths of OA and AC Solution : AB = 2√15 cm AB is CHORD of circle  C2 Radius of C2  = 4 cm   and center O' O'A = O'B = 4cm intersection of PQ  & AB  =  M AM = BM = AB/2 = √15 cm O'A² = O'M² + AM² => 4² = O'M² + (√15)² => 16 = O'M² +15 => O'M² = 1 => O'M =1 O'Q = 4 cm OQ = 3cm => OO'  = 1 cm O'M =1 => OM = 1 + 1 = 2 cm OA² = OM² + AM² => OA² = 2² + (√15)² => OA² = 4 + 15 => OA = √19 cm OC² = OM² + CM² => 3² = 2² + CM² =>  CM² = 5 => CM = √5  cm AC​ = AM - CM  = √15 - √5 = √5(√3 - 1)  cm OA = √19 cm AC​ =  √5(√3 - 1)  cm LEARN More: Two circles touch internally at x the smaller circle passing through ... brainly.in/question/13955799 in the following figure , two circles touch each other internally in a ... brainly.in/question/15536860 Two circle touch each other internally in APOINT A.The Radius of the ... brainly.in/question/8050868