Answer:

Step-by-step explanation:
The equation of a circle has the following format:

In which r is the radius(half the diameter) and the centre is the point 
Centered at the origin
This means that 
Passing through the point(0,10)
The radius is the distance of any point in which the circle passes to the centre.
Using the formula for the distance between two points.

So


Answer:
7.05
Step-by-step explanation:
sqrt(50) = sqrt(25 * 2) = sqrt(25) * sqrt(2) = 5sqrt(2) = 5 * 1.41 = 7.05
Answer:
B. -5 - 1/8
Step-by-step explanation:
(-1/2) * 10 = -5
(-1/2) * 1/4 = -1/8
(-1/2)(10 + 1/4) = -5 - 1/8
Answer:
We have the equation,

i.e. 
i.e. 
It is required to find a system of equations having infinite solutions.
We know that,
'When the equations are dependent or their graphs are same, the system of equations has infinite number of solutions'.
So, we can take any equation having same graph as that of
.
Let, us take 
So, from the graph of these equations below, we get the system of equations having infinite solutions as,
and
.