To find the value of z, we can use the fact that SU is a midsegment of triangle RTV.
Since SU is a midsegment, it divides the base RV into two equal segments. So, RV is equal to twice the length of SU.
Given that SU = z - 28, we can set up the equation:
RV = 2(SU)
z = 2(z - 28)
z = 56