Use the image to answer the question.

An illustration shows a coordinate plane. The x-axis and the y-axis range from negative 6 to 6 in one unit increments. Six points are plotted on the plane. Two right triangles are graphed on the plane. Three points are plotted in the first quadrant. Point A is plotted at the coordinates left parenthesis 3 comma 2 right parenthesis, Point B is plotted at left parenthesis 3 comma 6 right parenthesis, and point C is plotted at left parenthesis 6 comma 2 right parenthesis. Points A and B, points B and C, and points C and A are connected by a dotted line segment to form triangle A B C. Three points are plotted in the second quadrant. Point D is plotted at the coordinates left parenthesis negative 3 comma 2 right parenthesis, Point E is plotted at left parenthesis negative 3 comma 6 right parenthesis, and point F is plotted at left parenthesis negative 6 comma 2 right parenthesis. Points D and E, points E and F, and points F and D are connected by line segments to form triangle D E F.

Triangle ABC
is reflected across the y
-axis to produce triangle DEF
. Which segment on DEF
is congruent to the segment BC
?

(1 point)
segment

1 answer

To determine which segment on triangle DEF is congruent to segment BC in triangle ABC, we first need to find the coordinates of the points forming segment BC.

In triangle ABC:

  • Point B is at (3, 6)
  • Point C is at (6, 2)

To find the length of segment BC, we can use the distance formula:

\[ \text{Length of } BC = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} \] Substituting the coordinates of points B and C:

\[ \text{Length of } BC = \sqrt{(6 - 3)^2 + (2 - 6)^2} = \sqrt{(3)^2 + (-4)^2} = \sqrt{9 + 16} = \sqrt{25} = 5 \]

Now, let's examine triangle DEF:

  • Point D is at (-3, 2)
  • Point E is at (-3, 6)
  • Point F is at (-6, 2)

To find the segment in triangle DEF that is congruent to segment BC, we examine the segments DE, EF, and FD.

  1. Segment DE (from D to E):

    • Length DE = \(\sqrt{((-3) - (-3))^2 + (6 - 2)^2} = \sqrt{0^2 + (4)^2} = \sqrt{16} = 4\)
  2. Segment EF (from E to F):

    • Length EF = \(\sqrt{((-6) - (-3))^2 + (2 - 6)^2} = \sqrt{(-3)^2 + (-4)^2} = \sqrt{9 + 16} = \sqrt{25} = 5\)
  3. Segment FD (from F to D):

    • Length FD = \(\sqrt{((-3) - (-6))^2 + (2 - 2)^2} = \sqrt{(3)^2 + 0^2} = \sqrt{9} = 3\)

Comparing the lengths:

  • Length DE = 4
  • Length EF = 5
  • Length FD = 3

The segment in triangle DEF that is congruent to segment BC (which has length 5) is segment EF.

Therefore, the final answer is:

segment EF