Math 3 EOC Review - Circles

Front

What is the formula for the area of a circle?

Back

A = πr², where A is the area and r is the radius.

Front

How do you find the circumference of a circle?

Back

C = 2πr, where C is the circumference and r is the radius.

Front

What is the relationship between the radius and diameter of a circle?

Back

The diameter is twice the radius: d = 2r.

Front

What is a central angle in a circle?

Back

A central angle is an angle whose vertex is at the center of the circle and whose sides intersect the circle.

Front

How do you convert degrees to radians?

Back

To convert degrees to radians, multiply by π/180.

Front

What is the length of an arc in a circle?

Back

Arc length = rθ, where r is the radius and θ is the central angle in radians.

Front

What is the equation of a circle in standard form?

Back

(x - h)² + (y - k)² = r², where (h, k) is the center and r is the radius.

Front

How do you find the radius from the equation of a circle?

Back

Rearrange the equation to standard form and identify r from (x - h)² + (y - k)² = r².

Front

What is the unit circle?

Back

The unit circle is a circle with a radius of 1 centered at the origin (0,0) in the coordinate plane.

Front

What are the coordinates of the point on the unit circle at 45 degrees?

Back

(√2/2, √2/2).