Bisecting an angle
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Bisecting an angle
description
Bisecting an angle. Draw an acute angle. How can we accurately bisect this angle without the use of a ruler or protractor ?. Prepare your set of compasses by lining the tip up with the point of your pencil. - PowerPoint PPT Presentation
Transcript of Bisecting an angle
Bisecting an angle
Draw an acute angle
How can we accurately bisect this angle without the use of a ruler or
protractor ?
Prepare your set of compasses by lining the tip up with the point of your pencil
Adjust the compasses to a setting that is smaller than the length of the
lines that create the angle
Draw an arc across each length of the angle.
Place the compasses on the point where one arc crosses a length and
draw a second arc
Without changing the compasses setting repeat for the other length so
that the two arcs cross.
Line a straightedge or ruler from the point of the angle to the point where the
arcs cross
Draw a line that runs from the point of the angle and through the point where
the arcs cross
Do NOT rub out your construction lines
Check your construction by measuring each of the angles created
Draw an obtuse angle
Prepare your set of compasses
Adjust the compasses to a setting that is smaller than the length of the
lines that create the angle
Draw an arc across each length of the angle.
Place the compass on the point where one arc crosses a length and
draw a second arc
Without changing the compass setting repeat for the other length so
that the two arcs cross.
Line a straightedge or ruler from the point of the angle to the point where the
arcs cross
Draw a line that runs from the point of the angle and through the point where
the arcs cross
Do NOT rub out your construction lines
Check your construction by measuring each of the angles created
Your turn
Draw 5 angles in your book and bisect each one making sure you clearly show
ALL of your construction lines
Perpendicular bisect of a line
Draw a line 6cm long
Prepare your set of compasses and open them to just over half the length
of the line
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
Place the point of the compasses on the other end of the line and draw the arcs
again
Line a straightedge or ruler up with the meeting points of the two sets of arcs
Draw a line that runs through each of the meeting points of the arcs
Do NOT rub out your construction lines
Check your construction by measuring one of the angles where the two lines
cross
Draw a line 5cm long
Prepare your set of compasses and open them to just over half the length
of the line
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
Place the point of the compasses on the other end of the line and draw the arcs
again
Line a straightedge or ruler up with the meeting points of the two sets of arcs
Draw a line that runs through each of the meeting points of the arcs
Do NOT rub out your construction lines
Check your construction by measuring one of the angles where the two lines
cross
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
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