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
38 Degrees multi-issue movement. It aims to empower UK citizens by providing easy ways for them to take action on the issues they care about, e.g., climate change, human rights and poverty. It claims "it’s 38 Degrees members who set priorities and we decide on what we campaign on together". They publish the results of their membership polls on their website. While 38 Degrees refers to 'members', there is no formal membership and these are simply people on its email mailing list. Each week 50,000 members, chosen at random, are asked to vote for their top priorities; only ones where there is