Answer:

Step-by-step explanation:
we know that
The area of a circle is equal to

we have

substitute

Remember that a central angle of
subtends for the area of a complete circle
so
by proportion
Find the area of the circle for a central angle of 

-1 17/20 and -1 8/10 can be compared easily if we give them common denominators. If we multiply the second fraction by 2, both fractions will have a denominator of 20.
8 * 2 = 16
10 * 2 = 20
New fraction: 16/20
-1 17/20 vs. - 1 16/20
-1 16/20 (-1 8/10) is greater. (For negative numbers, you can tell which one is greater by determining which one is closest to zero.)
E, 56, because you have 28 dollars, and you have to multiply that by two to get half dollars. 28*2=56.