Answer:
ABD = 140
DBC = 40
Explanation:
What is shown is a supplementary angle. These types of angles equal 180 degrees.
So that means whatever angle measures is in the supplementary angle added together would equal 180.
The equation to solve this would be (15x - 4) + (5x - 8) = 180
First, I would combine like terms. The 15x and 5x can be combined together to make 20x and the -4 and -8 would be equal to -12.
The simplified equation is now 20x - 12 = 180.
Next, we need to get rid of the 12. So we add 12 to both sides.
(20x - 12) + 12 leaves 20x by itself
180 + 12 = 192
Our equation is now 20x = 192
Next, we have to make sure that the x is by itself. To do this, we have to divide each side by 20.
20x/20 leaves us with just x.
192/20 is 9.6
x is equal to 9.6
Finally, we plug in the variable's value back into the angle measures to find their value.
15(9.6) - 4 = 140
5(9.6) - 8 = 40
Therefore, ABD is 140 degrees and angle DBC is 40 degrees.
Checking our work:
To check if our work is right, we can add up the angle measures to see if it's equal to 180.
140 + 40 is 180, so we are correct.
I apologize if that was a lot to read, but I hope you understand!