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
360 Degrees of Billy Paul was similarly enthusiastic in discussing how Paul's sound developed over the years from the early club jazz of "Feelin' Good at the Cadillac Club" (1968) to the merging of jazz and soul on "Going East" (1971): "and then we did Billy's "360 Degrees" album and it all came together with "Me & Mrs. Jones." During his appearance on "Soul Train" in October 1972, Paul was asked by host Don Cornelius whether he had a jazz background. Paul used the opportunity to promote his new album and highlight its diverse styles: “That's very correct. I've been singing since I was 11.