A place for students to explore mathematics.
pl correct the qn no.2(ptolemy,s theorem)AB.CD+AD.BC=AC.BD (not AC.AD)
pl explain the second step of third qn.(PQ^2=AB^2-(a-b)^2)
Vijayan Sir , both AP and BQ are perpendicular to XY , so AP is parallel to BQ. If we construct a ray from Q parallel to AB which intersect AP at say S , then triangle PQS will be a right angle triangle with angle P = 90°(Radius is perpendicular to tangent) , from there we can apply Pythagoras Theorem in triangle PQS.
Vijayan Sir , corrected the mistake. Thank you.