Vertical angles are congruent due to the fact that they intersect. If they did not, they would in fact be parallel. (last section)
Answer:
The radius of the balloon is increasing at a rate of 4 feet per minute.
Step-by-step explanation:
We are given the following in the question:

Volume of sphere is given by

where r is the radius of the balloon.
Instant radius, r = 2 ft
Rate of change of volume =

Putting values, we get,

Thus, the radius of the balloon is increasing at a rate of 4 feet per minute.
Dana:
Starts with 25 = 25
Spends 10 = 25 - 10 = 15
Received 50 = 15 + 50 = 65
New tires cost 75 = 65 - 75 = -10
Tracey:
Starts with 50 = 50
Gets gas for 25 = 50 - 25 = 25
Received 100 = 25 + 125 = 125
Purchased boots for 150 = 125 - 150 = -25
Tracey ends up with the least amount of money after their purchases.
Hope this helps! :)
The answer to this question is 1/6