MHB Using Angles on the Same Arc Theorem

[markosheehan]

View attachment 6471im trying to use angles on the same arc theorem

 

[Opalg]

im trying to use angles on the same arc theorem

Yes, the same arc theorem will certainly come into it. I suggest that you draw the lines $AL$ and $BC$ in the diagram, and then look for an external angle of the triangle $BCD$.

 

[markosheehan]

sadly i still can't see it... I've drawn these lines. all i can see now is angleCAL and angleCBL

 

[Opalg]

sadly i still can't see it... I've drawn these lines. all i can see now is angleCAL and angleCBL

That's right! Angle $CBL$ is an external angle of the triangle $BCD$, so it is the sum of the two opposite angles.

 

[markosheehan]

see it now