Answer: (x+7)^2 + (y-4)^2 = 121 or (x+7)^2 + (y-4)^2 = 11^2
Step-by-step explanation:
Equation of the circle is:
, which is the center
and the radius ![r^2](https://tex.z-dn.net/?f=r%5E2)
-Place the center (-7,4) and radius 11 onto that equation:
(if simplified radius needed)
or
![(x+7)^2(y-4)^2=11^2](https://tex.z-dn.net/?f=%28x%2B7%29%5E2%28y-4%29%5E2%3D11%5E2)
Using proportions, it is found that the speed of the runners are of 16 mph and of 20 mph.
<h3>What is a proportion?</h3>
A proportion is a fraction of a total amount.
After 30 minutes, the runners are 2 miles apart, hence the second runner is 4 miles per hour faster than the second, that is:
.
The first runner's speed is 4/5 of the speed of the second runner, hence:
![v_1 = \frac{4}{5}v_2](https://tex.z-dn.net/?f=v_1%20%3D%20%5Cfrac%7B4%7D%7B5%7Dv_2)
![v_1 = \frac{4}{5}(v_1 + 4)](https://tex.z-dn.net/?f=v_1%20%3D%20%5Cfrac%7B4%7D%7B5%7D%28v_1%20%2B%204%29)
![\frac{1}{5}v_1 = \frac{16}{5}](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B5%7Dv_1%20%3D%20%5Cfrac%7B16%7D%7B5%7D)
![v_1 = 16](https://tex.z-dn.net/?f=v_1%20%3D%2016)
![v_2 = 16 + 4 = 20](https://tex.z-dn.net/?f=v_2%20%3D%2016%20%2B%204%20%3D%2020)
Hence, the speed of the runners are of 16 mph and of 20 mph.
More can be learned about proportions at brainly.com/question/24863377
Answer:
Since a fraction represents a division, we should do that division to know what the value of a fraction is. The larger numerator, the larger the value of the fraction will be; and the larger denominator, the smaller the fraction will be. ...
Step-by-step explanation: