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Published byAusten Cox Modified over 9 years ago
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Constructions
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Find the perpendicular line to L 1 through the external point P. Note that the perpendicular bisector of the segment will not go through point P.
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Do you understand ? We can not use the fish on points A and B.
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Let us find 2 points on the line that are equidistant from point P. Why ? So we can go fishing. It’s a fluke ! Catfish ?
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Swing a compass from point P through the segment.
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This will create a segment cd which has P on its perpendicular bisector. This technique will be called …. The Smile technique
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Now we construct the fish using points c and d. Swing an arc from point c.
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Swing an arc from point d. Construct a line through the blue points of intersections.
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Note that the procedure is just a Smile and a Fish.
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Let us try this again. Create the smile. Create a perpendicular line though P.
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Note that the segment needs to be extended. Now, we are ready to construct the fish.
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Swing arc from point c. Swing arc from point d. Construct line through the points of arc intersections.
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Review To construct a perpendicular line from an external point to a given line, there are 2 steps. A Smile and A Fish
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Note that the perpendicular bisector of the segment will not go through point P. Construct a perpendicular line through point P.
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Do you think you know how to construct the perpendicular through P ? Correct ! A smile and a fish. Look
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First the smile. Now the fish. Construct an arc from X Construct line through the points of arc intersections. Construct an arc from y
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Summary Note that the technique for constructing a perpendicular to a line from an exterior point is the same as constructing a perpendicular to a line through a point on the line. A Smile and a Fish.
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Constructing a // line thru a Pt.
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Construct a line through P which intersects
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Duplicate the arc at point P.
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Set the compass to the distance between the arc intersection points on
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Swing an arc from bottom point across the top point.
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From above swing an arc from top point across the bottom point. Construct // line from the intersection point to point P
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Summary To construct a perpendicular line through either an external or an internal point the technique is called… A Smile and a Fish.
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Summary To construct a parallel line through an external point, just construct a non- parallel line through the external point. Then duplicate an angle below to the same relative position above.
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To construct a parallel line to an existing line though an external point 1. Construct a line through both the external point and the existing line. P
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To construct a parallel line to an existing line though an external point 1. Construct a line through both the external point and the existing line. 2. Copy the new top angle to the right to point P directly above it. P
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To construct a parallel line to an existing line though an external point 1. Construct a line through both the external point and the existing line. 2. Copy the new top angle to the right to point P directly above it. P 3. Construct the // line through point P and arc intersection point. Voila !
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C’est fini. Good day and good luck. A Senior Citizen Production That’s all folks.
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