GMAT Math Questions | Coordinate Geometry Q1

The question given below is a GMAT Math problem solving question in Coordinate Geometry. The radius of the circle and the coordinates of the center of the circle are provided. The task is to find the equation of the circle. This GMAT sample question is an easy question - a GMAT sub 600 level question.

Question 1: What is the equation of a circle whose radius is 6 units and is centered at (3, 2)?

1. x² + y² + 6x - 4y = 23
2. x² + y² - 6x + 4y = 23
3. x² + y² + 6x + 4y = 23
4. x² + y² - 6x - 4y = -23
5. x² + y² - 6x - 4y = 23

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Video Explanation

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Explanatory Answer | GMAT Equation of Circle

Generalized form of equation of a circle

Equation of a circle with center (a, b) and radius 'r' units is (x - a)² + (y - b)² = r²
Therefore, the equation of this circle = (x - 3)² + (y - 2)² = 6²
i.e., x² - 6x + 9 + y² - 4y + 4 = 36
or x² + y² - 6x - 4y = 23

Choice E is the correct answer.