The square root of 2<span>, often known as </span>root 2<span>, </span>radical 2<span>, or </span>Pythagoras' constant<span>, and written as </span><span>√2</span><span>, is the positive alg</span>ebraic number <span> that, when multiplied by itself, gives the number 2</span><span>. Technically, it is called the </span>principal square root of 2<span>, to distinguish it from the negative number with the same property.</span>
