<PRE><B>Question 192077</B>
Draw  a  rough  sketch  of  two  similar  triangles
label  sides  carefully

as  triangles  are  similar,  sides  are  proportional

per  of  given  triangle  abc  =  9 + 18 + 21 = 48.

per  of  new  triangle  is  112

as  perimeters  vary  as  scale  factor  to  1st  power

sf  =  112/48  =2 1/3  =7/3

xy  =  (7/3)ab =7/3 * 9 = 21
yz  = (7/3) bc  = 7/3*18 = 42
xz = (7/3) ac = 7/3*21 = 49

checking  per  2nd  triangle  = 21+42+49= 112  ok</PRE>