Tuesday, June 25, 2013

Trisecting a Right Angle

Let BAC be the give right angle.

  • With centre A and any convenient radius , draw an arc cutting AB at Q and AC at P
  • With the same radius and centres P and Q , draw arcs cutting the arc of step a) at R and S respectively. 
  • Draw lines joining A with P and Q. AP and AQ trisect the right angle BAC.
                 Thus ∠BAR = ∠RAS = ∠SAC = 1/3 ∠BAC
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Saturday, June 22, 2013

Division of Line Segment-Unequal Parts

Let AB be the given line segment to be divided into unequal parts say 1/6 ,1/5 ,1/ 4 ,1/3 ,1/ 2 .
  • Draw a line segment AB of given length. 
  • Draw perpendiculars AD and BC at points A and B. Complete the rectangle ABCD 
  • Join diagonals AC and BD intersecting at E. 
  • Draw perpendicular from E on AB and find intersection point F. 
  • Now AF = 1/ 2 AB
  •  Join D and F. The segment FD intersects the diagonal AC at G. Drop perpendicular from G to A. Then AH = 1/3 AB
  • Similarly make constructions as given in the figure to obtain 1/ 4 AB , 1/5 AB and 1/6 AB
This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Wednesday, June 19, 2013

Perpendicular to a Line - 4

Following are the steps for construction of a perpendicular to a line from a point outside it. In this construction, the arcs are shown as circles. 
  1. Let AB be the given line and P is the point outside it 
  2. With A as centre and radius AP, draw an arc cutting the given line at C. 
  3. With C as centre and radius CP, draw an arc cutting the arc of step 2 at R. 
  4. Draw line segment joining PR intersecting AB at Q.
PQ is the required perpendicular. Drag Point P and see the effect. This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Tuesday, June 18, 2013

Perpendicular to a Line Segment - 3

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Saturday, June 15, 2013

Perpendicular to Line Segment - 2

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com