Construct an isosceles triangle whose base is 8cm and altitude 4cm and then another triangle whose sides are 1 1/2 times the corresponding sides of the isosceles triangle.

Steps of construction:

1. Draw a base BC of length 8 cm.
2. Draw the perpendicular bisector of BC and name it PQ. Let it intersect BC in M.
3. From M, mark an arc A at a distance of 4 cm on PQ.
4. Join B−A and C−B. △ABC is the first isosceles triangle.
5. Extend BC and BA. Place the pointed end of the compass at C and mark an arc of radius CM on the opposite side of M on the extended segment BC. Mark the point as D (Since CM is half of BC, BD will be BC + 0.5BC = 1.5BC)
6. From D, draw a line parallel to AC and let it intersect the extended segment AB at E. △EBD is the required similar triangle.