2023 New style Student Supplies Engineering Standard Drawing Sets Stationery

There are two kinds of right-angle triangles, which are common right-angle triangles and isosceles right-angle triangles. In a right triangle, the two sides adjacent to the right angle are called right angles, and the side opposite the right angle is called hypotenuse. The right side of a right triangle is also called a "chord". If two right-angle sides are not the same length, the shorter side is called "hook" and the longer side is called "strand".

The ruler should not be mixed with a knife or metal stationery. When mixed with a pen, the pen cover must be put on. The ruler has sharp parts. Pay attention when using it to avoid scratching. Be sure to prevent exposure to the sun and long-term sunshine, and keep away from kindling, so as not to affect the accuracy of the measuring instrument and cause danger. It is better not to clean the ruler with a brush.