Answer:
1]
2]
3]
4]
Step-by-step explanation:
Given:-measure angle DCA = 18 degree
line AB II line DC
Solution:-
1] measure angle DCA and measure angle CAB are interior alternate angles and interior alternate angles are equal.
------------------ (Equation 1)
Therefore the equation for statement number 1 is 
2]Sum of interior angles of triangle is equal to 180 degree.
In Triangle ABC,
measure angle A+measure angle B+measure angle C=180 degree
Therefore the equation for statement number 2 is measure angle A+measure angle B+measure angle C=180 degree
3] In Triangle ABC,


![measure\ angle\ A=18\ degree---------------(from\ equation\ [tex]measure\ angle\ A+measure\ angle\ B+measure\ angle\ C=180\ degree](https://tex.z-dn.net/?f=measure%5C%20angle%5C%20A%3D18%5C%20degree---------------%28from%5C%20equation%5C%20%3Cstrong%3E%5Btex%5Dmeasure%5C%20angle%5C%20A%2Bmeasure%5C%20angle%5C%20B%2Bmeasure%5C%20angle%5C%20C%3D180%5C%20degree)
Now substituting the value of angles we get,

Therefore the equation for statement number 
4] After solving the equation 2 we get,




Therefore value of 