From what distance would our sun have an angular diameter of 7 arc seconds? If an observer travels away from our sun, at what distance would our sun occupy 7 arc seconds of space?
From us, the Sun is visible around a half grad, which is $\approx$ 30 arc min = 1800 arc seconds.

To get to 7 arc seconds, you need to go 1800/7 times farther away, so the result is around 250 AU.