The valueof is 9. Now substitutethis valuebackinto the expressionsto determinethe measuresof the
two anglesin the diagram.
The two anglesin the diagrammeasure27º and 153º.You can checkto makesure thesenumbersare
accurateby verifyingif they are supplementary.
VerticalAngles
Now that you understandsupplementaryand complementaryangles,you can examinemorecomplicated
situations.Specialanglerelationshipsare formedwhentwo lines intersect,and you can use your knowledge
of linearpairsof anglesto exploreeachanglefurther.
Verticalanglesare definedas two non-adjacentanglesformedby intersectinglines.In the diagrambelow,
and are verticalangles. Also, and are verticalangles.Supposethat you know. You can use that informationto find the measurementof all the
otherangles.For example, and mustbe supplementarysincethey are a linearpair. So, to find
, subtract100º from 180º.