The equation x ^ 2 - 2x + y ^ 2 - 4y = 20 defines a circle in the xy-coordinate plane What is the radius of the circle?

I'll set up the problem and you can do the calculation

Step-by-step explanation:

we need to complete the squares to get the equation in the general form:

where h = the x coordinate of the center

k = the y coordinate of the center

r = the radius

so looking at

we can see that if use -1 as the constant we have

doing the same for y

we can use -2 as the constant (basically you that the s

quare of the y coefficient )

so now we have to add or subtract the constant on the RHS to see what the square of the radius is according to the general form of the equation at the top

20 +1+4=25

Take the square root and you have the radius

answer: option a.

step-by-step explanation:

you know that the quadrilateral opqr ( a four sided figure) is inscribed in circle. this means that all its vertices are on the circle.

then, by definition, the opposite angles of the quadrilateral are supplementary, this means that the sum of their measures is 180 degrees.

you can observe in the figure that the angles ∠opq   and the angle ∠orq   are opposite, therefore:

then, can be used to d to calculate the measure of ∠opq