. In quadrilateral ABCD ,AP and BP are bisectors of <A and <B respectively.Then find <APB if C=60 and D=130​

Snell's law asserts that n1/n2 = sin α2/sin α1. Overview of optics and light refraction. Because the ratio n1/n2 is a constant for any given wavelength of light, the ratio of the two sines is also a constant for any angle.