William Oughtred (1574-1660)

William Oughtred, English mathematician and theologian, vicar of Shalford and rector of Albury, was the first to use the symbol \(∠\) to refer to an angle in his book Trigonometria (1657). The symbol replaced the symbol < previously used and introduced by French mathematician Pierre Herigone, in his book Cursus Mathematicus (1634).