Q21 of 47 Page 1

Construct an isosceles triangle with base 8 cm and altitude 4 cm. Construct another triangle whose sides are 2/3 times the corresponding sides of the isosceles triangle.

Steps of construction:

1. Draw base line BC of length 8 cm.


2. Draw the perpendicular bisector XX’ of BC, cutting BC at D.


3. With D as center and radius 4 cm, draw an arc cutting XX’ at A.


4. Join AB and AC.


5. Thus, the isosceles triangle ABC whose base is 8 cm and height 4 cm is formed.


6. Along BX, mark three points B1, B2 and B3 such that BB1 = B1B2, B1B2 = B2B3.


7. Join CB3.


8. From B2, draw a line C’B2 which is parallel to CB3.


9. From C’, draw A’C’∥AC meeting AB at A’.


10. Then A’BC’ is the required triangle whose sides are 2/3rd of the isosceles triangle.



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