what is the y-coordinate for point A?

Question

Point A has an x coordinate of −2 and lies in a circle with a center at (0, 0) and a radius of 5.

To the nearest tenth, what is the y-coordinate for point A?

4.5

4.6

4.7

4.8

Please show all the steps you used to solve the problem. I would really appreciate it.

Answer 1

The equation of the circle is x² + y² = 25.

Put x=-2 into this equation.

Then y² = 21

There are 2 values of y which satisfy the question and you should now be able to find them...use your calculator to find the square root (or do it the old-fashioned way or by Newton's method!).