A short steel tape measure or steel measuring tape is a flexible ruler and used to measure distance. It consists of a metal blade with linear-measurement markings, pocket protective case, stopper button, belt clip, end hook and hand stripe. It is a common measuring tool.
A caliper is a device used to measure the dimensions of an object. Many types of calipers permit reading out a measurement on a ruled scale, a dial, or a digital display. Some calipers can be as simple as a compass with inward or outward-facing points, but no scale.
It is used by carpenters and machinists for checking the correctness of right angles, as a guide when drawing lines on materials before cutting, or for locating holes.
A compass (or pair of compasses) is a drawing tool that can be used to draw circles or arcs, parts of circles. They can also be used to measure distances, in particular on maps. Compasses can be used for mathematics, drafting, navigation, and more.
A protractor is a device used in drafting and drawing: it's mainly used for drawing and measuring angles. Don't show up to geometry without your protractor! In math class, you use many tools, such as a calculator. Another is the protractor, which is handy when you're studying geometry.
