Bisecting Angles
We at askmath believe that educational material should be free for everyone. Please use the content of this website for indepth understanding of the concepts. Additionally, we have created and posted videos on our youtube.
We also offer One to One / Group Tutoring sessions / Homework help for Mathematics from Grade 4th to 12th for algebra, geometry, trigonometry, precalculus, and calculus for US, UK, Europe, South east Asia and UAE students.
Affiliations with Schools & Educational institutions are also welcome.
Please reach out to us on [email protected] / Whatsapp +919998367796 / Skype id: anitagovilkar.abhijit
We will be happy to post videos as per your requirements also. Do write to us.
Construction of Bisecting Angles
Using a protractor draw are angle of measure 80
^{0}.Bisect the given angle.
Step 1: Draw a ray OA.
Step 2:With the help of protractor draw an angle AOB of measure 80
^{0}
Step 3: With center O and a convenient radius draw an arc cutting arms OA and OB at P and Q respectively.
Step 4: With center P and radius more than halflength of PQ, draw an arc.
Step 5: With center Q and same radius as in the step 4, draw another arc intersecting the arc drawn in the step 4 at R.
Step 6: Join OR and Produce it to form a ray OX the angle AOX is the angle of measure 40
^{0} ( one half of 80
^{0})
Construction of Angles 60^{0},120^{0}and 180^{0}
Step 1 : Draw a line segment AB of any length.
Step 2 : Draw an arc of any radius with center A, which cuts AB
at P.
Step 3 : With same radius and center at P draw another arc,
which cuts earlier arc at Q.
Step 4 : Join AQ.
Step 5 : ∠BAD = 60
^{0}
Step 4 : With same radius and centre at Q draw another arc
which cut the first arc at R.
Step 5 : Join A and R by drawing AC.
Step 6 : ∠CAB is the required 120° angle.
Bisectors of angles 
Angles 
0^{0} and 60^{0} 
30^{0}

60^{0} and 120^{0} 
90^{0}

0^{0} and 90^{0} 
45^{0} 
60^{0} and 90^{0} 
75^{0} 
90^{0} and 120^{0} 
105^{0} 
120^{0} and 180^{0} 
150^{0} 
Geometrical Constructions
• Basic Geometric Constructions
• Construction of Line Segment
• Bisecting a Line Segment
• Constructing Angles
• Bisecting Angles
• Constructing Parallel Lines
• Construction of Triangle (SSS)
• SAS Triangle Construction
• ASA Triangle Construction
• HL Triangle Construction (Rhs construction)
• Constructing Quadrilaterals
• Constructing Triangles(when sum of sides or perimeter is given)
Home Page