Given that ad and bc are parallel, find the value of x.

Therefore the value of x is 15.

Step-by-step explanation:

Given:

AD || BC

m∠ B = (9x + 15)°

m∠ A = (3x - 15)°

To Find:

x = ?

Solution:

AD || BC       ...............Given

If two lines are parallel and sum of the interior angles are supplementary.

i.e m∠ B and m∠ A are interior between Parallel lines.

∴

Substituting the given values we get

∴

Therefore the value of x is 15.

hdjd

step-by-step explanation:

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