Answer:
x= 30 units
Step-by-step explanation:
so the small triangle of sides 3 and 6 is similar to the big triangle of side 3+15 and 6+ x units.(by A.A.A.axiom)
now since the triangles are similar their sides become proportional
i.e.
3/6= (15+3)/(6+x)
or, 1/2 = 18/(6+x)
or 6+x= 36
therefore x=30
