Question

PLEASE HELP ME WITH THIS.. :)

A, B and C are the vertices of a triangle.
A has coordinates (4, 6)
B has coordinates (2,-2)
C has coordinates (-2,-4)
D is the midpoint of AB.
E is the midpoint of AC.
Prove that DE is parallel to BC.
You must show each stage of your working. WORTH 4 MARKS. THANKS

Answer 1

Explanation:

Use midpoint formula to find the coordinates of each midpoint.

(x, y) = (½ (x₁ + x₂), ½(y₁ + y₂))

The coordinates of B and C are given.

Coordinates of D:

(x, y) = (½ (4 + 2), ½(6 + -2))

(x, y) = (3, 2)

Coordinates of E:

(x, y) = (½ (4 + -2), ½(6 + -4))

(x, y) = (1, 1)

Slope of DE:

m = Δy / Δx

m = (2 − 1) / (3 − 1)

m = 1/2

Slope of BC:

m = Δy / Δx

m = (-2 − -4) / (2 − -2)

m = 1/2

Therefore, DE is parallel to BC.