Right angle of what a right angle is, namely two straight lines intersecting to form two equal and adjacent angles. The straight lines which form right angles are called perpendicular. Euclid uses right angles in definitions 11 and 12 to define acute angles (those smaller than a right angle) and obtuse angles (those greater than a right angle). Two angles are called complementary if their sum is a right angle. Book 1 Postulate 4 states that all right angles are equal, which allows Euclid to use a right angle as a unit to measure other angles with. Euclid's commentator Proclus gave a
Lonely Planet Six Degrees Lonely Planet Six Degrees Lonely Planet Six Degrees is Lonely Planet's flagship travel show, hosted by Asha Gill and Toby Amies. The show is centered on unique people living within locations, rather than simply famous tourist attractions, with one of the hosts meeting with one contact in a specific country, who in turn leads them to another contact, and so on, following the idea of six degrees of separation. In the first season Asha travelled to Mumbai, Buenos Aires, Kuala Lumpur, Melbourne, Auckland, Cape Town, London, and Singapore; while Toby travelled to Sydney, New York City, Havana, Hong Kong, Berlin,