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

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

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.

Direction: Consider the following for the items that follow:

A triangle ABC is inscribed in the circle x² + y² = 100. B and C have coordinates (6, 8) and (-8, 6) respectively.

What is BAC equal to?