Unit 7 Circles Flashcard

Front

What is the formula to calculate the circumference of a circle?

Back

The circumference (C) of a circle is calculated using the formula: C = πd or C = 2πr, where d is the diameter and r is the radius.

Front

What is the diameter of a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

Front

How do you find the radius of a circle if you know the diameter?

Back

The radius (r) is half of the diameter (d): r = d/2.

Front

What is the standard form of a circle's equation?

Back

The standard form of a circle's equation is (x-h)² + (y-k)² = r², where (h, k) is the center and r is the radius.

Front

What does the term 'circumference' refer to in relation to circles?

Back

Circumference refers to the total distance around the circle.

Front

If a circle has a radius of 7 meters, what is its circumference?

Back

C = 2πr = 2π(7) ≈ 43.98 meters.

Front

What is the area of a circle?

Back

The area (A) of a circle is calculated using the formula: A = πr².

Front

How do you convert the equation of a circle from general form to standard form?

Back

To convert from general form (Ax² + Ay² + Bx + Cy + D = 0) to standard form, complete the square for x and y.

Front

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

Back

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

Front

If a circle has a circumference of 31.4 meters, what is its diameter?

Back

Using C = πd, the diameter d = C/π = 31.4/π ≈ 10 meters.