Advanced MathMediumCircumference of a circle through a given point
Advanced Math practice question
In the xy-plane, a circle centred at the origin passes through the point (6, 8). The circumference of the circle can be written as kπ. What is the value of k?
Answer: 20
The radius is √(36 + 64) = 10, so the circumference is 2π(10) = 20π and k = 20.
Common wrong answers
- If you answered 10
- 10 is the radius.
- If you answered 14
- 14 is 6 + 8.
- If you answered 100
- 100 is r², which gives the area as 100π.
More Advanced Math questions
- Medium
What are the solutions to x² − 5x + 6 = 0? - Medium
The graph of f(x) = (x − 3)² + 4 is a parabola. What are the coordinates of its vertex? - Medium
If x² − 2x − 8 = (x + 2)(x − a), what is the value of a? - Medium
If √(x + 5) = 4, what is the value of x? - Medium
If f(x) = x + 3 and g(x) = 2x, what is f(g(4))? - Medium
What are the solutions to x² + 6x + 8 = 0?
Not affiliated with the College Board. SAT is a trademark of the College Board.