# Unknown angles on lines

• Aug 6th 2010, 04:14 PM
haftakhan
Unknown angles on lines
Attachment 18460

i want to know how to solve these two questions.
Its a Microsoft office file with two figures in it.
• Aug 6th 2010, 04:37 PM
masoug
The first question can be figured out, assuming that the two lines are parallel...

Bisect the angle x with a parallel line to the other two.
Then the parallel line property can determine the two angle measures adjacent to x.
If the lines are not parallel, then this method won't work.

-Masoug
• Aug 7th 2010, 02:26 AM
haftakhan
Can u explain it a bit more ?
and what about the 2nd figure ?
• Aug 7th 2010, 03:26 AM
Unknown008
In the diagram masoug posted, can you see the 'Z' formed by the parallel lines and the diagonals?
You should know that angles that are in the corners of the 'Z' are equal.

From this, you get to know the 56 and 41 angles.

Now, total angle is 360. You have 56 and 41. So the remaining is x = 360 - (41 + 56) = 360 - 97 = 263 degrees.

For the next one, look at the sketch, and use what you know to find X.

http://i33.tinypic.com/nf1p34.png

Find angles a and b first. X should come easy if you learned what to do in the first part.

Of course, there are more ways to do it, but I'd like you to do it the way you solved the first part.
• Aug 7th 2010, 03:35 AM
haftakhan
But why did he write 115 in his attached figure.that confused me.Now i can understand it.thanks
• Aug 7th 2010, 03:37 AM
Unknown008
Well, his answer is wrong because you can clearly see that the angle is a reflex angle, but 115 is obtuse. I hope you understand it (Happy)
• Aug 7th 2010, 03:39 AM
haftakhan
a=360-247=113

b=360-248=112

so 113+112=225
and 360-225=135=x
• Aug 7th 2010, 03:42 AM
Unknown008
You missed something.

a = (360 - 90) - 247
b = (360 - 90) - 248

Can you try again?
• Aug 7th 2010, 03:45 AM
haftakhan
i get it

a = (360 - 90) - 247=23
b = (360 - 90) - 248=22

a+b=23+22=45

x=360-45=315
• Aug 7th 2010, 03:47 AM
Unknown008
Great! Well done! (Happy)