The equation of a circle is $x^2 + y^2 = 42.25$ Find the radius of the circle. - Edexcel - GCSE Maths - Question 16 - 2018 - Paper 2

The standard form of the equation of a circle is given by:

$x^2 + y^2 = r^2$

where $r$ is the radius. From the equation provided, we see that:

$r^2 = 42.25$

To find the radius, we take the square root of both sides:

r = rac{1}{2} \sqrt{169}
Thus, the radius of the circle can be calculated as:

$r = \sqrt{42.25} \approx 6.5$