So you question is most likely about a triangle DEF with the 3 angles being named D, E, F. The triangle would look something like the image attached below.
If that is what is being asked then i need more info to answer but
By Definition it would be 180 degrees.
Answer:

Step-by-step explanation:
Given



Required
Find x
If
i.e. If AB is parallel to CD, then

Substitute values for ABC and BCD

Collect Like Terms


Multiply through by 





Answer:
a) response variable
Step-by-step explanation:
The response variable is the variable that depends on other variables such as the independent or explanatory variable, it is the variable that is being tested. The response variable is also called the dependent variable.
In linear regression, the y variable is referred to as the response variable while the x variable is referred to as the explanatory or independent variable.
In this case the y variable is "the number of times they cough in a day" and this variation depends on the x variable "number of cigarettes a person smokes in a day".
Answer:
48
Step-by-step explanation:
48 is divisble by all of them