Measuring Angles and Segments Section 1-4

Measuring Segments The distance between any two points on a horizontal or vertical line  ABSOLUTE VALUE OF THE DIFFERENCE OF THE COORDINATES  AB = |a – b|

Congruent Segments Two or more segments with the same length Figures are congruent Measures are equal

Postulate 1-6 Segment Addition Postulate If three points A, B, and C are collinear, and B is between A and C, then: AB + BC = AC A B C

If DT = 60, find the value of x. Then find DS and St D ST 2x - 8 3x - 12

Angles Right Angle – angle with measure of 90 degrees Acute Angle – angle with measure less than 90 degrees Obtuse Angle – angle with measure greater than 90 degrees but less than180 degrees Straight Angle – angle with measure of 180 degrees

Postulate 1-8 Angle Addition Postulate If point B is in the interior of <AOC, then m<AOB + m<BOC = m<AOC A O B C

Postulate 1-8 ** Angle Addition Postulate ** If <AOC is a straight angle, then m<AOB + m<BOC = 180 A O B C

Congruent Angles Angles with the same measure Figures are congruent Measures are equal

Angles Degree –Unit of measure for measuring angles Protractor –Instrument used to measure angles