Given:
Angles of the quadrilateral are 100°, 120°, 100° and x°.
To find:
The value of x.
Solution:
The sum of the angle measures of the quadrilateral is 360°.
[tex]\Rightarrow 100^\circ+120^\circ+100^\circ+x^\circ=360^\circ[/tex]
[tex]\Rightarrow 320^\circ+x^\circ=360^\circ[/tex]
Subtract 320° from both sides.
[tex]\Rightarrow 320^\circ+x^\circ-320^\circ=360^\circ-320^\circ[/tex]
[tex]\Rightarrow x^\circ=40^\circ[/tex]
The equation of 320 + x = 360.
The value of x is 40.
