SAT circle formulas - which ones should I know?

Hey guys, I'm prepping for the SAT math section, and I want to be prepared for any questions involving circles. What are the essential circle formulas I should memorize for the test? Any advice is appreciated!

Hey there! It's great that you're preparing for the SAT math section. Circle-related questions do come up, and it's essential to know some basic formulas. Here are the key circle formulas and concepts you should be familiar with:

1. Circumference: The formula for the circumference (C) of a circle is C = 2πr, where r is the radius of the circle.

2. Area: The formula for the area (A) of a circle is A = πr^2, where r is the radius of the circle.

3. Diameter: The diameter (d) of a circle is the distance across the circle through its center. The diameter is equal to twice the radius (d = 2r).

4. Chords: A chord is a line segment whose endpoints are on the circle. The longest chord in a circle is its diameter.

5. Arcs: An arc is a section of a circle's circumference. The length of an arc (s) can be calculated using the formula s = rθ, where r is the radius of the circle and θ is the measure of the central angle (in radians) subtended by the arc.

6. Sectors: A sector is the region enclosed by two radii of a circle and the arc connecting their endpoints. The area of a sector (Asector) can be calculated using the formula Asector = (1/2)r^2θ, where r is the radius of the circle and θ is the measure of the central angle (in radians) subtended by the arc.

7. Central angle: The central angle (θ) is the angle formed by two radii connecting the center of the circle to the endpoints of an arc. To convert a central angle from degrees to radians, use the conversion factor π radians = 180 degrees.

These formulas and concepts should have you covered for most circle-related questions on the SAT math section. Make sure to practice solving problems involving circles to get comfortable with applying these formulas. Good luck with your SAT prep!