What is the radius of a circle with the equation x2 + y2 – 14x + 10y = 250? A) 9 units B) 12 units C) 15 units D) 18 units

Respuesta :

first, we have to change the General equation in to standard equation:

Answer:

Option (d) is correct.

Radius of given equation is 18 units.

Step-by-step explanation:

Given : The equation of circle as [tex]x^2+y^2-14x+10y=250[/tex]

We have to find the radius of given circle.

Consider the given equation of circle [tex]x^2+y^2-14x+10y=250[/tex]

The standard equation of circle with center (h,k) and radius r is given as

[tex](x-h)^2+(y-k)^2=r^2[/tex]

Rewriting in standard form, we have,

Grouping x and y variables, we have,

[tex]\left(x^2-14x\right)+\left(y^2+10y\right)=250[/tex]

Convert x terms to perfect square term by adding 49 both side, we have,

[tex]\left(x^2-14x+49\right)+\left(y^2+10y\right)=250+49[/tex]

Simplify, we have,

[tex]\left(x-7\right)^2+\left(y^2+10y\right)=250+49[/tex]

Convert y  terms to perfect square term by adding 25 both side, we have,

[tex]\left(x-7\right)^2+\left(y^2+10y+25\right)=250+49+25[/tex]

Simplify, we have,

[tex]\left(x-7\right)^2+\left(y+5\right)^2=324[/tex]

Thus, standard form is

[tex]\left(x-7\right)^2+\left(y-\left(-5\right)\right)^2=18^2[/tex]

Thus, radius of given equation is 18 units.