Equation of a circle

The equation of a circle is (x² – 4x + 3) + (y² – 6y+ 8) = 0. Which of the following statements are correct? I. The end points of a diameter of the circle are at (1, 2) and (3, 4).

II. The end points of a diameter of the circle are at (1, 4) and (3, 2).

III. The end points of a diameter of the circle are at (2, 4) and (4, 2).

Select the answer using the code given below.

What is the equation of the circle whose diameter is 10 cm and the equation of two of its diameters are x + y = 0 and x – y = 0?

A square is inscribed in a circle x² + y² + 2x + 2y + 1 =0 and its sides are parallel to coordinate axes. Which one of the following is a vertex of the square?

The circle x² + y² - 2kx - 2ky + k² = 0 touches the x-axis at P and y-axis at Q.

 What is PQ equal to?