Aking cobra is 4.237 meters long. round the length tothe nearest meter

The nearest meter is 4 meters because the 7 would round the 3 to a 4, but a 4 wouldn't round up the 2. Even if the 4 rounded up the 2 to a 3, it still wouldn't be enough to round the 4 up to a 5. In other words, 4 and below will not round up anything, but a 5 or above will round up anything (as far as basics go).

Equatorial triangle and obtuce angle