In Ex 11.2 Of This Chapter In Third question Why Did we Take 2cm Below the angle as in other questions we took the cms on the angles made??

Asked by  | 7th Mar, 2013, 08:41: PM

Expert Answer:

In the third question, the difference between two sides of the triangle is given and when the difference is given, two cases arise. The two are given below:
 

   Eg: Construct a triangle with base of length 7.5 cm, the difference of the other two sides 2.5 cm, and one base angle of 45°

          Given          : In ΔABC, base BC = 7.5 cm, the difference of the other two sides, AB – AC or AC – AB = 2.5 cm and one base angle is 45°.

          Required      : To construct the ΔABC,

          CASE (i) AB – AC = 2.5 cm.

          Steps of Construction:

  1. Draw BC = 7.5 cm.
  2. At B, construct angleCBX = 45°.
  3. From BX, cut off BD = 2.5 cm.
  4. Join CD.
  5. Draw the perpendicular bisector RS of CD intersecting BX at a point A.
  6. Join AC. Then, ABC is the required triangle.
 

CASE (ii) AC – AB = 2.5 cm

Steps of Construction:

  1. Draw BC = 7.5 cm.
  2. At B, construct angleCBX = 45° and produce XB to form a line XBX’.
  3. From BX’, cut off BD’ = 2.5 cm.
  4. Join CD’.
  5. Draw perpendicular bisector RS of CD’ intersecting BX at a point A.
Join AC. Then, ABC is the required triangle.
 
 
To know more about contructions, you can go through the videos of this chapter available on our site.

Answered by  | 7th Mar, 2013, 10:28: PM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.