In the figure below, if be is the perpendicular bisector of ad, what is the value of x?

Both sides are the same, set them to equal and solve for X.

3X +4 = X +12

Subtract 4 from each side:

3X = x + 8

Subtract 1X from each side:

2X = 8

Divide both sides by 2:

X = 8/2

X = 4

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional