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

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


   

Question 91634: Help.
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, 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 Simplify the square root (note: If you need help with simplifying the square root, check out this solver)

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

So the radius is 5 units