Tangential quadrilateral all of whose sides are tangent to a single conic section has three diagonals that meet at a point. From a tangential quadrilateral, one can form a hexagon with two 180° angles, by placing two new vertices at two opposite points of tangency; all six of the sides of this hexagon lie on lines tangent to the inscribed circle, so its diagonals meet at a point. But two of these diagonals are the same as the diagonals of the tangential quadrilateral, and the third diagonal of the hexagon is the line through two opposite points of tangency. Repeating this same
A Plane Is Born Mark visits the Popular Flying Association Rally at Cranfield to see some of the 3000 or so home-built and vintage aircraft that have flown in for the weekend. He talks to Graham Newby, the Chairman of the PFA and the Editor of Flyer Magazine who takes him through the perils and pit falls of building his own plane. - Test Flight Mark travels to the Europa Factory in North Yorkshire where after seeing all the components that go into making a kit, he takes a test flight with Technical Director Andy Draper. In part 2, he starts his private pilot