J.R. S. answered 04/22/20
Ph.D. University Professor with 10+ years Tutoring Experience
T1 = initial temperature in Kelvin = 282K
V1 = initial volume = 3.45 L
T2 = final temperature in Kelvin = ?
V2 = final volume = 5.25 L
Assuming the pressure is constant (i.e. an expandable container), you are dealing with Charles' Law
V1/T1 = V2/T2
3.45 L/282K = 5.25 L/T2
T2 = 429K