Answer:
1][tex]measure\ angle\ DCA=measure\ angle\ CAB=18\ degree[/tex]
2][tex]measure\ angle\ A+measure\ angle\ B+measure\ angle\ C=180\ degree[/tex]
3][tex]18\ degree+3x+3x=180\ degree[/tex]
4][tex]x=27[/tex]
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.
[tex]measure\ angle\ DCA=measure\ angle\ CAB=18\ degree[/tex]------------------ (Equation 1)
Therefore the equation for statement number 1 is [tex]measure\ angle\ DCA=measure\ angle\ CAB=18\ degree[/tex]
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,
[tex]measure\ angle\ B=3x---------------(Given)[/tex]
[tex]measure\ angle\ C=3x---------------(Given)[/tex]
[tex]measure\ angle\ A=18\ degree---------------(from\ equation\ [tex]measure\ angle\ A+measure\ angle\ B+measure\ angle\ C=180\ degree[/tex]
Now substituting the value of angles we get,
[tex]18\ degree+3x+3x=180\ degree-------------(Equation\ 2)[/tex]
Therefore the equation for statement number [tex]3\ is\ 18\ degree+3x+3x=180\ degree[/tex]
4] After solving the equation 2 we get,
[tex]18+3x+3x=180[/tex]
[tex]6x=180-18[/tex]
[tex]6x=162[/tex]
[tex]x=27\ degree[/tex]
Therefore value of [tex]x=27\ degree[/tex]