Answer:
a
Step-by-step explanation:
The circumference (C) of a circle is calculated as
C = 2πr ( r is the radius ) , then
C = 2π × 20 = 40π
1 1/2 * 2 3/4 =
3/2 * 11/4 =
33/8 =
4 1/8 miles in 2 3/4 hrs
The answer is

.
Before we rationalize the denominator, we must simplify the numerator and denominator. We evaluate the square root on the top, and combine like terms on the bottom:

To rationalize the denominator, we multiply by the conjugate. The conjugate is found by making the imaginary term of the complex number, the i part, the opposite sign. The conjugate of -2-i is -2+i:
Answer:
63.2 = y
Step-by-step explanation:
The perimeter is the sum of all the sides
P = 7.8+ y+37.6 + y
171.8 = 7.8+ y+37.6 + y
Combine like terms
171.8 = 45.4 + 2y
Subtract 45.4 from both sides
171.8-45.4 = 45.4 + 2y -45.4
126.4 = 2y
Divide each side by 2
126.4/2 = 2y/2
63.2 = y
As you probably know there is a difference between mean and median -- the mean acts as a measure of the average, and on the other hand median measures the middle number. The median in this is 15 and the mean is also 15.