Question

Type the correct answer in each box.
A circle is centered at the point (-7, -1) and passes through the point (8, 7).
The radius of the circle is _____
units. The point (-15, __) lies on this circle.

Answer 1

The radius of the circle is 17 uints and the point (-15,-16) or (-15,14) lies on the circle.

step by step explanation is here,

centre of circle(h,k)=(-7,-1)

if the circle passes through the point (8,7)

then the distance between (8,7) and (-7,-1) represents the radius.

so, r^2= (x2-x1)^2 + (y2-y1)^2

or, r^2=(-7-8)^2 +(-1-7)^2

or, r^2=(-15)^2 +(-8)^2

or, r^2=225+64

or, r^2=289

or, r=17 units

now the equation of circle is

(x-h)^2 +(y-k)^2 =r^2

or, (x+7)^2 +(y+1)^2 =289

or, x^2 +14x +49 + y^2 + 2y+ 1=289

or, x^2 + y^2 + 14x +2y-239=0

puttimg x=-15,

or, (-15)^2 + y^2 +14×(-15) + 2y -239=0

or, y^2 + 2y -239+225-210=0

or, y^2 + 2y -224=0

If you slove y, then you will get 14 and -16.

Answer 2

Answer:

Radius = 17; The point (-15, -16) lies on this circle.

Step-by-step explanation:

Took it on Edmentum/Plato. Correct Answer. Enjoy :)