What is the radius of the circle whose equation is x² + y² = 8?

Solution:

The general equation of the circle is given by (x - h)² + (y - k)² = r²

Where, (h,k) is the center

r is the radius 

Given, the equation of the circle is x² + y² = 8

So, r² = 8

Taking square root,

r = 2√2

Therefore, the radius of the circle is 2√2 units.

Example: What is the radius of the circle whose equation is x² + y² = 9?

Solution:

The general equation of the circle is given by (x - h)² + (y - k)² = r²

Where, (h,k) is the center

r is the radius 

Given, the equation of the circle is x² + y² = 9

So, r² = 9

Taking square root,

r = 3

Therefore, the radius of the circle is 3 units.

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What is the radius of the circle whose equation is x² + y² = 8?

Summary:

The radius of the circle whose equation is x² + y² = 8 is 2√2 units.