The answer is 180 degrees.
A right angle formed at the edge of any circle will always create an arc of 180 degrees. This is true no matter where it is placed and no matter the side lengths.
Let the year represents x axis and consumption represents y axis.
Since 2010 is the initial year, x=0
and 2013 is third year , so x=3
Co-ordinates are (0,8.938)(3,10.480)
Exponential formula is 
Putting the value of x in the above formula from 1st coordinate,

As
= 1
this gives a= 8.938
Now using the 2nd coordinate

putting the value of a in it we have

taking cube roots on both sides we get
b= 1.05448
Now putting the values of a and b in the exponential formula-

In the year 2028, x=28
so,

y= 39.474
Hence oil consumption per day in 2028 will be 39.474 million barrels.
The ratio of similar areas is the square of the ratio of the scale factor.
Circle R's sector is (5/2)² = 25/4 the area of Circle Q's sector.
A. hope this helps I’m pretty sure it’s right though