Protractor on the dial from 180°, as the dial is graduated from opposite zero marks to 90° each way. Since the spaces, both on the main scale and the Vernier scale, are numbered both to the right and to the left from zero, any angle can be measured. The readings can be taken either to the right or to the left, according to the direction in which the zero on the main scale is moved. Reading the Vernier scale: The bevel protractor Vernier scale may have graduations of 5′ (minutes) or 1/12°. Each space on the Vernier scale is 5′ less
Protractor traditionally been one-sided. This is thought to be because early manufacturing methods set the tone of future production. Unfortunately, the two number scales on a one-sided protractor often confuse learners when first learning to measure and draw angles. However, in 2009, Jake Adamson, a maths teacher working at Musselburgh Grammar School invented and patented the first two sided protractor trademarked "The Angler". This was a double sided protractor with one scale on each side, avoiding the confusion of having two scales together and enabling easier measuring and drawing of angles. "The Angler" protractor has been widely adopted by schools in