Bisecting Angles
Construction of Bisecting AnglesUsing 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 half-length 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)