The answer would be 101/20
Answer:
x=9
Step-by-step explanation:
All measurements of the interior angles equals up to 180 degrees when added together, therefore add them all together and set it equal to 180.
7x+2+4x+7+8x=180
-Combine like terms
19x+9=180
-Subtract 9 on both sides
19x=171
-Divide by 19
x=9
21 its 21 because it is 21