A) 8cm
Step-by-step explaination:
TR = 4 + x
Also,
TR = 8 + (2x - 16)
Therefore,
4 + x = 8 + 2x - 16
4 + x = (8 - 16) + 2x
4 + x = -8 + 2x
4 + 8 = 2x - x
12 = x
SR = 2x - 16
= 2(12) - 16
= 24 - 16
= 8
