Answer:
140°
Step-by-step explanation:
We know that all of these angles here are part of a hexagon, meaning that their angle measures will all add up to 720°.
We can use what we already know and find what CDE and DEF will add up to.
[tex]145+90+160+115=510\\720-510=210[/tex]
Now, assuming x is the measure of DEF, we can create an equation for this.
[tex]x + 2x = 210\\3x = 210\\x = 70[/tex]
This is the measure of DEF, but it asks for CDE, which is twice the size of DEF. So
[tex]70\cdot2=140[/tex]
We can double check this is right by adding up all the measures.
[tex]145+90+160+115+140+70=720[/tex]
Hope this helped!
