[size=150][b][color=#ff0000]Supplementary Angles are any pair of angles whose sum (adding) is equal to 180 degrees ([url=https://www.mathopenref.com/anglestraight.html]straight angle[/url]). [/color][/b][/size]

[size=150][b][color=#351c75]Remember that pairs are things that come in twos. For example, the pair of dice above is called a pair because there are two of them. Can you think of any other types of pairs? [/color][/b][/size]

[size=200][b][color=#ff0000]So, any PAIR of angles that have a [url=https://www.mathsisfun.com/definitions/sum.html]sum[/url] of 180 degrees are supplementary angles. [/color][/b][/size]

[size=150][b][color=#0000ff]We can use that truth to solve problems in Geometry![/color][/b][/size]

[b][color=#ff0000]We know that line m is a straight line. [br][/color][/b][b][color=#ff0000]If line m is a straight line, then we know its measure is 180 degrees[br]We know that the larger angle has a measure of 118 degrees, but we don't know what the measure of its supplemental angle is (x[math]^\circ[/math][/color][/b][size=150][b][color=#ff0000]).[/color][/b][/size]

[size=150][b][color=#0000ff]I set up an equation based on the postulate: [/color][/b][/size] [size=150][b][color=#b45f06]x + 118 = 180[/color][/b][/size][br][b][size=150][color=#0000ff][br]I subtract 118 from both sides of the equal sign [/color][color=#b45f06]x = 62[/color][/size][/b]