Answer:
61
Step-by-step explanation:
a = 17
d = 21 - 17 = 4
12th day: 17 + 4(12 - 1)
17 + 44
61
Answer:
D
Step-by-step explanation:
First add all the simple line up so;

Then use Pythagoras to work out the lengths of the remaining lines

So to three decimal places it would be;
