Fatou marks the points (3, -5) and (-2, -7) on the coordinate plane. Then, she finds the distance between them. What is this distance rounded up to the nearest tenth of a unit?

1 answer

To find the distance between the two points \((3, -5)\) and \((-2, -7)\) on the coordinate plane, we can use the distance formula:

\[ d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \]

Here, \((x_1, y_1) = (3, -5)\) and \((x_2, y_2) = (-2, -7)\).

Let's substitute these values into the formula:

  1. Calculate \(x_2 - x_1\): \[ x_2 - x_1 = -2 - 3 = -5 \]

  2. Calculate \(y_2 - y_1\): \[ y_2 - y_1 = -7 - (-5) = -7 + 5 = -2 \]

  3. Now square these differences: \[ (x_2 - x_1)^2 = (-5)^2 = 25 \] \[ (y_2 - y_1)^2 = (-2)^2 = 4 \]

  4. Add these squares: \[ (x_2 - x_1)^2 + (y_2 - y_1)^2 = 25 + 4 = 29 \]

  5. Now take the square root to find the distance: \[ d = \sqrt{29} \]

We approximate \(\sqrt{29}\). It lies between \(\sqrt{25} = 5\) and \(\sqrt{36} = 6\), and we can find it using a calculator:

\[ \sqrt{29} \approx 5.385 \]

To round this distance to the nearest tenth, we observe the first decimal digit:

\[ 5.385 \approx 5.4 \text{ when rounded to the nearest tenth} \]

Thus, the distance between the points \((3, -5)\) and \((-2, -7)\) rounded up to the nearest tenth of a unit is

\[ \boxed{5.4} \]