The change of the weather balloon would be 90% increase. to get the percentage of change we have to subtract 50 ft to 95 ft, it will then give us the 45 ft change. Then we have to divide 45 ft by 50 ft times 100, it will give us 90%. Then since the change and percentage of change is positive then the change could be describe as increasing.
Well divide them. 2/3=0.666 repeated. So use a bar over the top of the third six.
I think the answer is A.
It's probably wanting you to use pythagorean theorem.
Do you have a picture to go with this? I can't help without the picture :(