Equation fo a circle:
Data:
Center: C(x₀,y₀).
radius: r
(x-x₀)²+(y-y₀)²=r²
In this equation:
(x+4)²+(y-6)²=25
C(-4,6)
r²=25 ⇒r=√25=5
Then, it´s radius is 5.
If, we have got two points:
A(x₁,y₁)
B(x₂,y₂)
The distance beetween the points is:
dist(A,B)=√[(x₂-x₁)²+(y₂-y₁)²]
Then:
A(-6,7)
B(-1,-5)
dist(A,B)=√[(-1+6)²+(-5-7)²]
dist (A,B)=√(5²+12²)
dist (A,B)=√(25+144)
dist (A,B)=√169
dist (A,B)=13
the distance between the points (-6,7) and (-1,-5) is 13.
