Type the circle equation as written and click the center or a crossing. The graph shows radius without completing the square. Desmos access is in Desmos on the ACT.
Equation in, center out
(x − h)² + (y − k)² = r² draws immediately. The algebra form is in the equation of a circle. Inequalities shade a region instead of a rim, in inequalities in Desmos.
If the circle is off the screen, set the window, in setting the window.
The bottom line
Graph the circle. Click the center. Read r from the equation or the grid.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
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