## What is the difference between a protractor and a compass?

The compass is used to draw circles and arcs, while the protractor helps you measure and make plane angles. Signing up for a geometry class means you’ll likely need two essential supplies: a compass and a protractor.

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## What is the use of protector?

protractor, any of a group of instruments used to construct and measure plane angles. The simplest protractor comprises a semicircular disk graduated in degrees—from 0° to 180°. It is an ancient device that was already in use during the 13th century.

**Why is it called a protractor?**

protractor (n.) 1610s, “one who lengthens (an action),” Modern Latin agent noun from Latin protrahere “to draw forward” (see protraction). Medieval Latin protractor meant “one who calls or drags another into court.” The surveying sense of “instrument for measuring and drawing angles on paper” is recorded from 1650s.

### What is a protractor used for in math?

GeometryProtractor / Calculation supported

### What is compass used for?

A compass is a device that indicates direction. It is one of the most important instruments for navigation. Magnetic compasses are the most well known type of compass.

**Why is a protractor called that?**

## Why is it called protractor?

## Who invented protractor?

Invented by the 19th-century German physicist Philipp von Jolly, it consists in its usual form of a long, delicate, helical spring suspended by one end in front of a graduated scale.

**What is a protractor in math kids?**

A protractor is a clear plastic device to measure angles from 0 degrees to 90 degrees. We can use a protractor to measure an angle in degrees.

### How do you draw an angle with a compass and protractor?

Draw a circle and an angle on a piece of paper using a protractor and a compass. On a secret piece of paper, write down the exact measurements of each. Close the compass (so there are no clues given). Hand the protractor, compass, and drawing to the first student in line.

### How do I measure angles with a protractor?

Protractors usually have two sets of numbers going in opposite directions. Be careful which one you use! When in doubt think “should this angle be bigger or smaller than 90°?” Have a Go Yourself! Try to measure the angles A, B and C inside the triangle. Drag the protractor and rotate it using arrow keys.

**How do you make an astrolabe with a protractor?**

You can make your own simple astrolabe using a protractor, plastic straw, 12-inch piece of string, and a metal weight (a small bolt or a washer works well). Tie one end of the string to the hole in the middle of your protractor.

## How do you find the altitude of a star with a protractor?

Locate Polaris, then use your astrolabe to find its altitude. Sight the star through the straw and note what degree the string lines up at on the protractor. (Read the inner set of numbers, from 0-90 degrees.) This number is the zenith angle. To find the altitude angle, subtract the zenith angle from 90 degrees.