Measuring Segments- We measure segments with a ruler or metersticks.

Measuring Angles- Angles are measured by the means of a protractor. Angles can be measured in degrees, radians, gradients. We shall use degrees as the angle measure. The measure of angle is the number of degrees one side is rotated from the other side.

Definition-
Acute Angle- Acute angle is an angle whose measure is greater than 0 but less than 90 degrees.
Right Angle- Right angle is an angle whose measure is exactly 90 degrees.
Obtuse Angle- Obtuse angle is an angle whose measure is greater than 90 but less than 180 degrees.
Straight Angle- Straight angle is an angle whose measure is exactly 180 degrees.

Parts of a degree- A degree is made up of 60 minutes. 1 minute is made of 60 seconds.
45 degrees 20 minutes 35 seconds is written as: 45º20'35"

Congruent Angles and Segments-

Definition- Congruent angles have the same degree measure.
Definition- Congruent segments have the same length.