Q9 of 805 Page 13

Construct an isosceles triangle whose base is 8 cm and altitude 4 cm and then another triangle whose sides are times the corresponding sides of the isosceles triangle.


In an isosceles triangle, median and altitude are the same.


Steps of Construction:


1. Draw base AB of side 8 cm.



2. Draw perpendicular bisector of AB.



3. Let perpendicular bisector intersect AB at point C.



4. Taking point C as center, and 4 cm radius, draw an arc intersecting perpendicular bisector at point D.



5. Join AD, and BD.



Δ ABC is the required triangle.


Now, we need to make a triangle which is its size.


Scale factor =


Steps of Construction:


1. Draw any ray AX making an acute angle with AB on the side opposite to the vertex D.



2. Mark 3 (greater of 2 and 3) points B1, B2, B3 on BX so that AB1 = B1B2 = B2B3.



3. Join B2B and draw a line through B3 parallel to B2B, to intersect AB extended at B’.



4. Draw a line through B’ parallel to the line BD to intersect AD extended at D’.



Thus, Δ AB’D’ is the required triangle.


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