Which of the following numbers is irrational?
3 squared
4 squared
-7/4
2/3

2/3 is the irrational number here.

3 ^2 = 9
4 ^ 2 = 16
- 7/4 = 1.75
2/3 = 0.666666..
Irrational number is one which cannot be written as a fractional form as it has repeating units.. here in 2/3 we see 6 is the repeating unit.

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct