Area of a circle is directly proportional to the square of radius of the circle while the circumference is proportional to the radius of the circle. This means that if the radius of a circle is increased x times, then its area will be increased to x^2 times the original area, and the circumference will increase to x times the original circumference.
Thus when the radius is doubled, or in other words if radius mad 2 time the original radius, the area of circle will become 2^2 = 4 time the original area. The circumference will become 2 times the original circumference.
We can calculate exact area and circumference of a circle from its radius using the following equations:
Area of circle = (pi/4)*r^2
Circumference of circle = 2*pi*r
Where r is the radius of the circle.
I know this is a lot, sorry.
Theos initial balance in his savings account = -$4
Final balance after making a deposit = $25
So, the overall change to his account = $ 29
We are given function: y= 
Where, x is the number of hours after 5a.m.
We need to approximates the number of people standing in line to catch a commuter train at 7 a.m.
From 5 a.m. to 7 a.m. total number of hours = 7-5 = 2 hours.
So, we need to plug x=2 in the given function.
Plugging x=2 in
, we get

Let us simplify it now.
2^2= 4.
Therefore,

= -20.524 + 63.642 - 3.333.
= 39.785 or 40 approximately.
Therefore, the number of people in line at 7 a.m. is approximately 40 people.
Option D.40 is correct option.
G^2+2=0,
g^2=-2
g= sqrt-2, not possible.
3g+1=0
3g=-1
g=-1/3
9 cannot be equal to zero for the last one.