False. When a quadrilateral has two sets of parallel sides ,like I drew below, all four corners form right angles.
Answer:
a = 12 and b = 18
Step-by-step explanation:
Given that,
8,a,b,27 are in geometric sequence.
For a GP, the nth term is given by :

Put n = 4

Put n = 2,

Put n = 3

So, the values of a and b is 12 and 18 respectively.