If the equation of a circle is (x + 5)2 + (y - 7)2 = 36, its radius is
To find the radius of a circle, we can compare the given equation to the standard form of a circle equation:
(x - h)² + (y - k)² = r²
In this case, the equation is already in standard form, with (h, k) representing the center of the circle and r representing the radius.
Comparing the given equation (x + 5)² + (y - 7)² = 36 to the standard form, we can see that the center of the circle is (-5, 7), and the radius squared is 36.
Therefore, the radius of the circle is the square root of 36, which is 6.
To find the radius of a circle given its equation, we can use the standard form of the equation of a circle:
(x - h)² + (y - k)² = r²
In this equation, (h, k) represents the coordinates of the circle's center, and r represents the radius.
Comparing this to the given equation, we can see that (h, k) = (-5, 7) and r² = 36.
To find the radius, we need to take the square root of r²:
r = √36
Simplifying, we find:
r = 6
Therefore, the radius of the circle is 6 units.
review the significance of the equation
(x-h)^2 + (y-k)^2 = r^2