Geometrical Constructions Maths - Geometrical Constructions

Have you looked at lamp posts on the roadside? How do they stand?

For the above explained construction, why must we take a distance greater than half of the length of AB? What will happen if we take a smaller distance?

When constructing a building, what is the method used to make sure that a wall is exactly upright? What does the mason in the picture have in his hand? What do you think is his purpose for using it?

Take a rectangular sheet of paper. Fold the paper so that the lower edge of the paper falls on its top edge, and fold it over again from right to left. Observe the two folds that have formed on the . paper. Verify that each fold is a perpendicular bisector of the other. Then measure the following distances. (Textbook pg. no. 91)
i. l(XP)
ii. l(XA)
iii. l(XB)
iv. l(YP)
v. l(YA)

You will observe that l(XP) = l(YP), l(XA) = l(YA) and l(XB) = l(YB)
Therefore we can conclude that all points on the vertical fold (perpendicular bisector) are equidistant from the endpoints of the horizontal fold.

The Perpendicular Bisector.

1. A wooden ‘yoke’ is used for pulling a bullock cart. How is the position of the yoke determined?
2. To do that, a rope is used to measure equal distances from the spine/midline of the bullock cart. Which geometrical property is used here?
3. Find out from the craftsmen or from other experienced persons, why this is done.

In the above construction, why must the distance in the compass be kept constant?

Draw line CD. Take any point M on the line. Using a protractor, draw a line perpendicular to line CD at the point M.

Draw a line AB. Using a compass, draw a line perpendicular to AB at point B.