Inscribed angle its intersection points equals half of the central angle subtended by the chord. See also Tangent lines to circles. The inscribed angle theorem is used in many proofs of elementary Euclidean geometry of the plane. A special case of the theorem is Thales' theorem, which states that the angle subtended by a diameter is always 90°, i.e., a right angle. As a consequence of the theorem, opposite angles of cyclic quadrilaterals sum to 180°; conversely, any quadrilateral for which this is true can be inscribed in a circle. As another example, the inscribed angle theorem is the basis for several
How Many More Years of the power chord. T-Bone Burnett said of the recording: The first major breakthrough Sam [Phillips] made was with Howlin' Wolf. That's when he started bringing the bass and drums up loud. Back in those days the bass and drums were background instruments; it was all about the horns and the piano, the melody instruments, and Sam brought the rhythm section right up front, and that became rock 'n' roll. That was a big shift... In some ways "How Many More Years" by Wolf would be the first rock ’n’ roll song because that has the guitar lick that became