For question 1:
Part i)
2.6 x 2.6 = 6.76 cm squared
No unit conversions needed
Part ii)
1.2 dm = 1.2 / 1000000 = 0.0000012 cm
0.0000012 x 0.0000012 = 0.00000000000144 cm squared
Question 2:
16.5dm = 16.5/ 1000 = 0.0165 m
0.0165 x 0.0165 = 0.00027225 m squared
I hope this has helped
It already is a decimal unless you mean a repeating decimal, it would be .26 with a line over the number.
Y/3.5= 25
(Hoped this help^)
This is how you solve it, and here is the answer!