Hey there!
A perpendicular line's slope to another line is always the negative reciprocal of slope.
If our line has a slope of two, we first must find the reciprocal, which is 1/2. Then, we put a negative on it.
Therefore, our equation is y=-1/2x+b.
I hope that this helps! Have a great day!
Answer:
OK, lets start by drawing a basic graph (the first one) so we can visualize.
We already know that the y coordinate of the circle's center is 
.
We know that the circle is tangent to the 
axis at 
That means the x coordinate of the center has to be 
, as the tangent is a point on the edge of the circle that touches a line at exactly one point.
The radius is the distance from the center of the circle to its edge. We know the center's location now, it is 
and a point on the edge of the circle (the tangent point) which is . so the distance between the points is 4 which is the radius (you can use the distance formula, but it's quite oblivious.)
We can imagine the circle should look like this (the second one):
Now we can piece together an equation
The equation of a circle is 
where 
is the center and 
is the radius. When we put the numbers in: we get 
which can be simplified into which is the answer.
Step-by-step explanation:
