GB-37-06-001 · Angle-bisector construction
On plain paper, draw angle ABC = 42°, with BA = BC = 5 cm. Using ruler and compasses, construct the bisector of angle ABC. Leave all arcs visible.
Constructions: Angle Bisector
Supplementary GCSE method — not covered in this booklet
Method
1) Draw arc from vertex B cutting both arms
2) From those two intersections draw equal-radius arcs meeting inside the angle
3) Draw straight line from B through intersection
Worked Example (GB-37-06-001)
1)
An arc centred at B intersects both arms.
2)
Equal-radius arcs from these intersections meet inside the angle.
3)
A straight ray from B through the arc intersection.
Ans =
Bisector divides the angle into two 21.0° angles.