Answer:
a
Step-by-step explanation:
We are given that
D is the mid-point of AB and E is the mid-point of AC.
We have to find the missing information in given proof of DE is equal to half of BC.
Proof:
D is the mid-point of AB and E is the mid-point of AC.
The coordinates of A are (2b,2c)
The coordinates of D are (b,c)
The coordinates of E are (a+b,c)
The coordinates of B are (0,0)
The coordinates of C are (2a,0)
Distance formula:[tex]\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}[/tex]
Using the formula
Length of BC=[tex]\sqrt{(2a)^2+(0-0)^2}=2a[/tex] units
Length of DE=[tex]\sqrt{(a+b-b)^2+(c-c)^2}=a[/tex] units
[tex]BC=2a=2\times DE[/tex]
[tex]DE=\frac{1}{2}BC[/tex]
Hence, proved.
Option A is true.