So, imagine the trainer is in the very middle of the circle and he is holding out a rope that's attached to the horse. The rope here from the trainer to the horse represents the radius of the circle. The horse trots around the trainer (middle point) in a circle.
The formula to find area of a circle is A = pi*r^2 (pi times r squared where r is radius)
We know that the radius of the "circle" here formed as the horse trots around the trainer is 31 (the 31 foot long rope).
So let r = 31 & plug the value into the formula to find circle area.
A = pi*31^2 = 3019.07054
The area is therefore 3019.07 square feet. (rounded)
And?... is that the question or is there more?
Answer:
12
Step-by-step explanation:
x = number of $1 bills
y = number of $5 bills
z = number of $10 bills
We know that:
x + y + z = 25 (total amount of bills)
x + 5y + 10z = 100 (total amount of money)
y = 4z (Given)
Substitute the third equation into the first one.
x + 4z + z = 25
x = 25 - 5z
Put this into the second equation.
(25 - 5z) + 5 (4z) + 10z = 100
Simplify and solve.
25 - 5z + 20z + 10z = 100
25z + 25 = 100
25z = 75
z = 3
Substitute this into y = 4z
y = 4 * 3
y = 12
So, there are 12 $5 bills.