Answer:
m<D = 20.7
Explanation:
Let's remember that all three angles in the interior must be equal to 180 degrees
Second, you're given the measure of tw angles with the thrid missing
Let's solve:
(5x-8)+ (4x-19)+ x = 180 .... x is the third angle which is not given
Now simplify:
5x- 8+ 4x- 19 +x = 180
Combine like terms:
10x -27 = 180
10x = 180+ 27
Now plug in the value of x into each of the angle measures:
5*20.7 - 8= 95. 5
4*20.7 - 19= 63.8
Now let's see how much is the other angle based on our data:
95.5+ 63.8+ x= 180
x= 180- 95.5 -63.8
m<D = 20.7
10x = 207
x= 207/10
x= 20.7