Question

Which point is on the circle centered at the origin with a radius of 5 units?

Answer 1

Answer:2, square root of 21 just took the test!

Step-by-step explanation:

Answer 2

Answer:

(2,√21)

Step-by-step explanation:

The circle centered at the origin has equation:

${x}^{2} + {y}^{2} = 25$

Any point that satisfies this equation lie on this circle.

When x=2, we substitute and solve for y.

${2}^{2} + {y}^{2} = 25 \\ 4 + {y}^{2} = 25 \\ {y}^{2} = 25 - 4 \\ {y}^{2} = 21$

Take square root to get:

$y = \pm \sqrt{21}$

Therefore (2,-√21) and (2,√21) are on this circle.

From the options, (2,√21) is the correct answer