SOLUTION: The point (2,0) is on a circle with the center(-1,4). Find the length of the radius.

Algebra ->  Circles -> SOLUTION: The point (2,0) is on a circle with the center(-1,4). Find the length of the radius.      Log On


   

Question 91337: The point (2,0) is on a circle with the center(-1,4). Find the length of the radius.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
To find the radius, you need to find the distance between (2,0) and (-1,4)


Start with the given distance formula
d=sqrt%28%28x%5B1%5D-x%5B2%5D%29%5E2%2B%28y%5B1%5D-y%5B2%5D%29%5E2%29 where is the first point and is the second point

d=sqrt%28%282--1%29%5E2%2B%280-4%29%5E2%29 Plug in x%5B1%5D=2, x%5B2%5D=-1, y%5B1%5D=0, y%5B2%5D=4

d=sqrt%28%283%29%5E2%2B%28-4%29%5E2%29 Evaluate 2--1 to get 3. Evaluate 0-4 to get -4.

d=sqrt%289%2B16%29 Square each value

d=sqrt%2825%29 Add

d=5

So the distance between (2,0) and (-1,4) is 5 units


So that means the radius is 5 units