In the given triangle,
it is given that,
U is the midpoint of RS, V is the midpoint of ST and W is the midpoint of RT
so,
UR = US
VT = VS
WT = WR
put the values,
UR = US
12 = US
so, RS = 2 x UR = 2 x 12 = 24
VT = VS
11 = 2x
x = 11/2
x = 5.5
so, TS = 2 x 11 = 22
WT = WR
3y = 15.9
y = 15.9/3
y = 5.3
so, RT = 2 x 15.9 = 31.8
also, UV = 1/2 RT
UV = 1/2 x 31.8 = 15.9
UW = 1/2x TS
UW = 1/2 x 22 = 11
VW = 1/2 RS
VW = 1/2 x 24 = 12