Answer:
Hey Im not sure I understand the question but I think the answer is
x=15
Explanation:
5x+ 3x+ 4x= 180,( I made it equal to 180 because that is the measure of angles for triangles)
add the x
12x= 180
divide
180/12
x=15
(EXTRA)
To prove it you can plug 15 into any of the x's to add it up and it will equal 180