It's already there.
To round 12.16 to the nearest tenth of a foot, you look at the digit in the hundredths place, which is 6. Since 6 is 5 or greater, you round up the digit in the tenths place (1) by one. Therefore, 12.16 rounded to the nearest tenth is 12.2 feet.
I think I know why nobody has answered this yet. There are no initial units. If it is 337.5 feet, then you are already there. If it is 337.5 yards, then that is 1012.5 feet. If it is 337.5 inches then it is 28.125 feet, which rounds to 28.1 (nearest tenth of foot).
12.48 rounded to the nearest tenth
3.5 feet
THe square root of 12 is: 3.5 rounded to the nearest tenth
12. 84 rounded to the nearest tenth is 12.8
12 percent of 52 = 6.24 Rounded to the nearest tenth = 6.2
The cone's perpendicular height is: 12 cm (the slant height is 13 cm)
12.2
4.0
12.00 = 12.0 = 12
12.0