Question

does the point (-4, 2) lie inside or outside or on the circle x^2 + y^2 = 25?​

Answer 1

Given equation of the Circle is ,

$\sf\implies x^2 + y^2 = 25$

And we need to tell that whether the point (-4,2) lies inside or outside the circle. On converting the equation into Standard form and determinimg the centre of the circle as ,

$\sf\implies (x-0)^2 +( y-0)^2 = 5 ^2$

Here we can say that ,

• Radius = 5 units

• Centre = (0,0)

Finding distance between the two points :-

$\sf\implies Distance = \sqrt{ (0+4)^2+(2-0)^2} \\\\\sf\implies Distance = \sqrt{ 16 + 4 } \\\\\sf\implies Distance =\sqrt{20}\\\\\sf\implies\red{ Distance = 4.47 }$

• Here we can see that the distance of point from centre is less than the radius.

Hence the point lies within the circle .

Answer 2

Answer:

inside the circle

Step-by-step explanation:

The equation of a circle centred at the origin is

x² + y² = r² ( r is the radius )

x² + y² = 25 ← is in this form

with r = $\sqrt{25$ = 5

Calculate the distance d from the centre to the point (- 4, 2 ) using the distance formula

d = $\sqrt{(x_{2}-x_{1})^2+(y_{2}-y_{1})^2 }$

with (x₁, y₁ ) = (0, 0) and (x₂, y₂ ) = (- 4, 2)

d= $\sqrt{(-4-0)^2+(2-0)^2}$

   = $\sqrt{(-4)^2+2^2}$

   = $\sqrt{16+4}$

    = $\sqrt{20}$

    ≈ 4.5 ( to 1 dec. place )

Since 4.5 is less than the radius of 5

Then (- 4, 2 ) lies inside the circle