Question

The point A is shown on the unit grid below.​

Answer 1

Answer:

Coordinates of point B are (3, 5) and (5, 3).

Step-by-step explanation:

Coordinates of point A → (1, 1)

Let the coordinates of point B are (x', y')

Formula for the distance between points (x, y) and (x', y') is,

d = $\sqrt{(x-x')^+(y-y')^2}$

AB = $\sqrt{(x-1)^+(y-1)^2}$

$2\sqrt{5}=\sqrt{(x-1)^2+(y-1)^2}$

$(2\sqrt{5})^2=(x-1)^2+(y-1)^2$

20 = (x - 1)² + (y - 1)²

Since point A lies on the intersection of two grid lines in the 1st quadrant, x and y must be the positive whole number.

For x = 0,

20 = (0 - 1)² + (y - 1)²

(y - 1)² = 20 - 1

y = 1 + √19

But y can't be a decimal, therefore, x = 0 is not the answer.

For x = 1

20 = (1 - 1)² + (y - 1)²

20 - 1 = (y - 1)²

y = 1 + √19

Not a whole number, so can't be the solution.

For x = 2,

20 = (2 - 1)² + (y - 1)²

y = 1 + √19

Not a whole number, therefore, not the answer.

For x = 3,

20 = (3 - 1)² + (y - 1)²

20 - 4 = (y - 1)²

y = 1 + √16

y = 5

Therefore, (3, 5) are coordinates of the point B.

For x = 4,

20 = (4 - 1)² + (y - 1)²

20 = 9 + (y - 1)²

y = 1 + √11

For x = 5,

20 = (5 - 1)² + (y - 1)²

20 - 16 = (y - 1)²

4 = (y - 1)²

y = 3

Therefore, (5, 3) the coordinates of point B.