PLS HELP!!A circle is centered at 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:Part 1) The radius of the circle is [tex]17\ units[/tex] Part 2) The points (15,14) and (-15,-16) lies on this circleStep-by-step explanation:Part 1we know thatThe distance between the center of the circle at point (-7,-1) and the point (8,7) is equal to the radius of the circlesothe formula to calculate the distance between two points is equal to [tex]d=\sqrt{(y2-y1)^{2}+(x2-x1)^{2}}[/tex] substitute the values[tex]r=\sqrt{(7+1)^{2}+(8+7)^{2}}[/tex] [tex]r=\sqrt{(8)^{2}+(15)^{2}}[/tex] [tex]r=\sqrt{289}}[/tex] [tex]r=17\ units[/tex] Part 2we know thatIf the point (-15,y) lies on the circle, then the ordered pair must be satisfy the equation of the circleThe equation of the circle is equal to[tex](x+7)^{2}+(y+1)^{2}=17^{2}[/tex] -----> equation of the circle in center radius formsubstitute the value of x=-15 in the equation and solve for y[tex](-15+7)^{2}+(y+1)^{2}=289[/tex][tex]64+(y+1)^{2}=289[/tex][tex](y+1)^{2}=289-64[/tex][tex](y+1)^{2}=225[/tex][tex]y+1=(+/-)15[/tex][tex]y=-1(+/-)15[/tex] so[tex]y=14[/tex][tex]y=-16[/tex]thereforeThe points (15,14) and (-15,-16) lies on this circlesee the attached figure to better understand the problem