Explain how you can round 25.691 to the greatest place.

The greatest place is the leftmost place. In 25.691, 2 is the greatest place and it is in the tens place. So, to round it to the nearest tens place, look at the number to the right of 2. Since that number is 5, change the 2 to 3. Then, change all  numbers except for the 2 to 0, making it 30.000. You can also write 30 and ignore the zeros to the right of the decimal.

i do not know the answer i am sorry

since the airplane is moving with constant speed then the distance travelled can be calculated by x=u*t

in km/h would be:

x=640*3.5=2.240 km

in m/s would be:

u=640 km/h= 640.000 m/h =640.000/ 3600 m/s =177.8 m/s

t= 3.5 h= 3.5 * 3600 s=12.600 s

then x=u*t= 177.8*12.600= 2.240.280 m