The lines a and b intersect at point D.

What is the value of z?

z =

http://static.k12.com/calms_media/media/1561000_1561500/1561011/1/78faf1bd5c48a3fe68a305b005ddfd42afbabb12/MS_IMC-1401104-109024.jpg

Question

The lines a and b intersect at point D.

 

What is the value of z?

 

z =    


http://static.k12.com/calms_media/media/1561000_1561500/1561011/1/78faf1bd5c48a3fe68a305b005ddfd42afbabb12/MS_IMC-1401104-109024.jpg

anonymous · Answer

z=12

anonymous · Answer

I'm not 100% sure, but I think that's the answer

anonymous · Answer

ohk thanks

radar · Answer

do you know how that was solved? @samantha121

anonymous · Answer

no she said she wasn't sure so idk if I should put that answer in

radar · Answer

Those two angles with the z terms are vertical angles because they are opposite each other at the intersection.  And vertical angles are equal.  In other words 
5z + 8 = 4z + 20     solve for z and she had it right.

anonymous · Answer

ohhh how do u solve that ...do u just plug in numbers?

radar · Answer

You just use algebra;
5z + 8 = 4z + 20     subtract 4z from both sides getting
z + 8 = 20   subtract 8 from both sides getting;
z = 12

radar · Answer

Those operations were done to isolate z on one side of the equal sign and get a numerical value on the other side of the equal sign.

radar · Answer

Good luck with your studies, it is lunch time for me.