The length of the curved surface is the circumfrence of a circle with radius r = 10/2 = 5 decimeters.
Length of curved surface = 2π x 5 = 10π ≈ 31.4 decimeters.
The answer is A because 2 multiplied by 9 is 18
In rounding, a number must be 5 or more to round up, and 4 or less to round down.
To round up to 4.26 you would need a number between 4.255 and 4.264
4.258 and 4.261 are two examples
Distance =

so plug in the coordinates and you will get 14.14 units