Example 1:
In Diagram below,PQ is parallel to RS. Determine the value of y.
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2014/03/Picture32-1.png)
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2014/03/Picture32-1.png)
Solution:
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2014/03/Picture33.png)
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2014/03/Picture33.png)
Construct a line parallel to PQ and passing through W.
a = 40o and b = 50o← (Alternate angles)
y = a + b
= 40o+ 50o
= 90o
Example 2:
In Diagram below, PSQ and STU are straight lines. Find the value of x.
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2014/03/Picture34.png)
![](http://pt3mathematics.blog.onlinetuition.com.my/wp-content/uploads/sites/6/2014/03/Picture34.png)