Write down the equation of a circle with a center O (-2.1) and a radius of 4cm

The circle equation has a canonical form:

(x – x0) ² + (y – y0) ² = R²;

Values used:

x0 – abscissa of the center of the circle;

y0 is the ordinate of the center of the circle;

R is the size of the radius of the circle.

By condition, the center of the circle is at the point O (-2; 1), or x0 = -2, y0 = 1. The radius of this circle is R = 4 cm.

Substituting all these data into the formula, we get the equation:

(x – (-2)) ² + (y – 1) ² = 4²;

(x + 2) ² + (y – 1) ² = 16.

The resulting equality is the desired equation of the circle.