When drawing lines perpendicular to one of the edges on boards and boards, it is worth remembering about a simple checking deposit. The angle will be right (90 degrees) then, when with side lengths equal to a multiple of three and four units (e.g. 30 i 40 cm), the length of the hypotenuse will be a multiple of five units, in this case 50 cm. Determining the right angle will be all the more accurate, we take the longer sides for measuring. The most common dimensions are the sides 30 40 cm or greater multiples of them.
