SOLUTION: in the accompanying diagram of parallelogram ABCD, m angle B=5x, and m angle c=2x+12. Find the number of degrees in < d. Is this the right approach? {{{2x+12+5x=180}}}

Algebra ->  Parallelograms -> SOLUTION: in the accompanying diagram of parallelogram ABCD, m angle B=5x, and m angle c=2x+12. Find the number of degrees in < d. Is this the right approach? {{{2x+12+5x=180}}}       Log On


   

Question 717041: in the accompanying diagram of parallelogram ABCD, m angle B=5x, and m angle c=2x+12.
Find the number of degrees in < d.
Is this the right approach? 2x%2B12%2B5x=180
12%2B6x=180
6x=168
x=28
then
B=5x=5%2828%29=140
and then angle d is equal or congruent to angle B so the answer is 140
Found 3 solutions by lynnlo, ikleyn, MathTherapy:
Answer by lynnlo(4176) About Me  (Show Source):
Answer by ikleyn(53475) About Me  (Show Source):
You can put this solution on YOUR website!
.
in the accompanying diagram of parallelogram ABCD, m angle B=5x, and m angle c=2x+12.
Find the number of degrees in Is this the right approach? 2x%2B12%2B5x=180
12%2B6x=180
6x=168
x=28
then
B=5x=5%2828%29=140
and then angle d is equal or congruent to angle B so the answer is 140
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Your calculations have internal errors, so they should be fixed and polished.
See my calculations below. 


2x + 12 + 5x = 180

12 + 7x = 180

7x  = 168

x = 168/7 = 24


B = 5x = 5*24 = 120

and then  angle d is equal or congruent to angle B so the answer is 120 degrees.

Now everything is correct.



Answer by MathTherapy(10622) About Me  (Show Source):
You can put this solution on YOUR website!
in the accompanying diagram of parallelogram ABCD, m angle B=5x, and m angle c=2x+12. 
Find the number of degrees in < d.

Is this the right approach? 2x%2B12%2B5x=180
                             12%2B6x=180
                               6x=168
                                x=28

then
                 B=5x=5%2828%29=140
and then  angle d is equal or congruent to angle B so the answer is 140

    2x + 12 + 5x = 180
         7x + 12 = 180
              7x = 168  <=== Should be THIS, instead of 6x = 168  
So, "x" actually = 168%2F7 = 24o

     So, ∠B = 5x = 5(24o) = 120o

As opposite ∠s of a parallelogram are CONGRUENT, ∠B = ∠D = 120o, also.