how do you find de, round to nearest 10th

Step-by-step explanation:

Observe in the figure given in the exercise that four right triangles are formed.

In this case you can use the following Trigonometric Identity to solve this exercise:

From the figure you can identify that:

Then, you can substitute values:

The next step is to solve for DE in order to find its value. This is:

Finally, rounding the result to the nearest tenth, you get that this is:

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

multiply then divide

step-by-step explanation: