Question

Use the image to answer the question.

Triangle A B C is plotted on a coordinate plane.
▼Click for Long Desc
The horizontal axis is labeled x and goes from negative 10 to 10 in intervals of 1 labeled every 5 units. The vertical axis is labeled y and goes from negative 10 to 10 in intervals of 1 labeled every 5 units. Vertex A is at left parenthesis negative 8 comma negative 2 right parenthesis, vertex B is at left parenthesis negative 5 comma 5 right parenthesis, and vertex C is at left parenthesis 5 comma 2 right parenthesis.

△ABC
is plotted on a coordinate plane.

If D is the is the midpoint of BC¯¯¯¯¯¯¯¯
, what is the length of median AD¯¯¯¯¯¯¯¯
?

(2 points)

5.8

5.3

8.1

9.7

Answer 1

Midpoint D of BC: D = ((-5+5)/2, (5+2)/2) = (0, 3.5).

Distance AD = sqrt[(0 - (-8))^2 + (3.5 - (-2))^2] = sqrt[8^2 + 5.5^2] = sqrt[64 + 30.25] = sqrt[94.25] ≈ 9.7.

Answer: 9.7.