Question 403069
STEP ONE:
realize that the TOTAL number of degrees in a triangle is 180. 


STEP TWO:
Let angle #1 = 'x' degrees
Let angle #2 = 'y' degrees
Let angle #3 = 'z' degrees


STEP THREE:
Now we can model the relationship as:

x + y + z = 180


STEP FOUR:
Realize from the problem statement that 

z = 2(x + y) 

and also that

x = y

so, 

z = 2(x + x) = 4x


STEP FIVE:
since 

x + y + z = 180 and since z = 4x we can now write the following

x + y + 4x = 180, 

and since x = y, we can now write the following

x + x + 4x = 180, and this is the same as saying that

6x = 180, and now by simple division

x = 180/6 = 30

so x = 30 and since y is the same as x, y is also = 30

and we already established that z = 4x so z = 120

the final answers:

x = 30 
y = 30
z = 120