Home / Digital SAT Math : Circles – Practice Questions

Digital SAT Math : Circles – Practice Questions

SAT MAth Practice questions – all topics

  • Geometry and Trigonometry Weightage: 15% Questions: 5-7
    • Area and volume
    • Lines, angles, and triangles
    • Right triangles and trigonometry
    • Circles

SAT MAth and English  – full syllabus practice tests

 Question  Foundation

In the xy-plane, a circle with radius 2 has center \((0,0)\). Which of the following is a equation of the circle?
A) \(x^2+y^2=2\)
B) \(x^2+y^2=4\)
C) \(x^2-y^2=2\)
D) \(x^2-y^2=4\)

▶️Answer/Explanation

Ans:B

The general equation of a circle with center \((h, k)\) and radius \(r\) is:
\[
(x – h)^2 + (y – k)^2 = r^2
\]

Center \((0,0)\)
Radius \(2\)

Substitute these values into the equation:
\[
(x – 0)^2 + (y – 0)^2 = 2^2
\]

Simplify:
\[
x^2 + y^2 = 4
\]

Question

\(x\)2-6\(x\)+\(y\)2-8\(y\)=0

The graph of the given equation in the \(xy\)-plane is a circle. What is the radius of the circle? 

  1. 2
  2. 3
  3. 4
  4. 5
Answer/Explanation

Ans: D

Question

In the \(xy\)-plane, a circle with radius 2 has center (0,0). Which of the following is a equation of the circle?

  1. \(x\)2+\(y\)2=2
  2. \(x\)2+\(y\)2=4
  3. \(x\)2-\(y\)2=2
  4. \(x\)2-\(y\)2=4
Answer/Explanation

Ans: B

Question

In the \(xy\)-plane, the points (-3, 10) and (3, 10) are endpoints of the diameter of a circle. Which equation represents this circle? 

  1. \(x\)2+(\(y\)-10)2=9
  2. (\(x\)+3)2+\(y\)2=36
  3. (\(x\)+3)2+(\(y\)-10)2=9
  4. (\(x\)+3)2+(\(y\)-10)2=36
Answer/Explanation

Ans: A

Question

\((x + 3)^{2} + (y – 7)^{2} = 100\)
In the \(xy\)-plane, the graph of the given equation is a circle. Which point \((x, y)\) lies on the circle? 

  1. (3, -4)
  2. (3, -1)
  3. (3, 1)
  4. (3, 4)
Answer/Explanation

Ans: B

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