Answer:
c=2.1 and d is, well check my explanation, theres a possible three answers because this website is , not the best
Explanation:
c is 3 divided by √2 which is 1.5√2 and in decimal its 2.12.... and so this rounds down to 2.1
d should be 1 but im guessing it messed up so its either 1√3 or 2√3 depending on where it is, and 1√3 rounds to 1.7 and 2√3 round to 3.5