1. Bisecting an angle

2. Draw an acute angle
How can we accurately bisect this angle without the use of a ruler or protractor ?

3. Prepare your set of compasses by lining the tip up with the point of your pencil

4. Adjust the compasses to a setting that is smaller than the length of the lines that create the angle

5. Draw an arc across each length of the angle.

6. Place the compasses on the point where one arc crosses a length and draw a second arc

7. Without changing the compasses setting repeat for the other length so that the two arcs cross.

8. Line a straightedge or ruler from the point of the angle to the point where the arcs cross

9. Draw a line that runs from the point of the angle and through the point where the arcs cross

10. Do NOT rub out your construction lines

11. Check your construction by measuring each of the angles created

12. Prepare your set of compasses
Draw an obtuse angle
Prepare your set of compasses

13. Adjust the compasses to a setting that is smaller than the length of the lines that create the angle

14. Draw an arc across each length of the angle.

15. Place the compass on the point where one arc crosses a length and draw a second arc

16. Without changing the compass setting repeat for the other length so that the two arcs cross.

17. Line a straightedge or ruler from the point of the angle to the point where the arcs cross

18. Draw a line that runs from the point of the angle and through the point where the arcs cross

19. Do NOT rub out your construction lines

20. Check your construction by measuring each of the angles created

21. Your turn
Draw 5 angles in your book and bisect each one making sure you clearly show ALL of your construction lines

22. Perpendicular bisect of a line

23. Draw a line 6cm long

24. Prepare your set of compasses and open them to just over half the length of the line

25. Place the point of the compasses on one end of the line and draw an arc above the line and another below the line. BE CAREFUL NOT TO LET THE COMPASSES MOVE

26. Place the point of the compasses on the other end of the line and draw the arcs again

27. Line a straightedge or ruler up with the meeting points of the two sets of arcs

28. Draw a line that runs through each of the meeting points of the arcs

29. Do NOT rub out your construction lines

30. Check your construction by measuring one of the angles where the two lines cross

31. Draw a line 5cm long

32. Prepare your set of compasses and open them to just over half the length of the line

33. Place the point of the compasses on one end of the line and draw an arc above the line and another below the line. BE CAREFUL NOT TO LET THE COMPASSES MOVE

34. Place the point of the compasses on the other end of the line and draw the arcs again

35. Line a straightedge or ruler up with the meeting points of the two sets of arcs

36. Draw a line that runs through each of the meeting points of the arcs

37. Do NOT rub out your construction lines

38. Check your construction by measuring one of the angles where the two lines cross

39. REMEMBER TO SHOW ALL OF YOUR CONSTRUCTION LINES
Your turn
Accurately draw each of the lines in your books and create a perpendicular bisector for each one
REMEMBER TO SHOW ALL OF YOUR CONSTRUCTION LINES
8cm
7cm
9cm