We know that the total number of students is 180, so 180 is the 100% of the students. Knowing this, we can set up a proportion and solve for x:
[tex] \frac{180}{100} = \frac{135}{x} [/tex]
[tex]x= \frac{(135)(100)}{180} [/tex]
x = 75%
We can conclude that 75% of the students attended the assembly.