Comments:The bisectorof an angleis a ray. If bisects, thereis not
anotherray that bisectsthe angle.The bisector(ray) of an angleisunique.UsingDiagrams
Now we applyour definitionsand postulatesto a geometricfigure.Whenmeasuresare givenon a figure,
we can assumethat the measurementson the figureare correct.We can also assumethat:
- Pointsthat appearto be collineararecollinear.
- Lines,rays,or segmentsthat appearto intersectdointersect.
- A ray that appearsto be in the interiorof an angleisin the interiorof the angle.
Wecannotassumethe followingfrom a diagram:
- That lines,segments,rays,or planesare parallelor perpendicular.
- That segmentsor anglesare congruent.
Thesemustbe statedor indicatedin the diagram.
The diagrambelowshowssomesegmentand anglemeasures.
Example 1
A.Is the midpointof Explainyour answer.No. is on , but.B.Is the midpointof Explainyour answer.Yes. is on , and =.C.Namean anglebisectorand the anglethat it bisects.bisects.