Therefore the sum of all interior angles of a pentagon is 540°.
2. Now make a table:
a = 360° - p
b = 180° - q
e = 180° - t
Now calculate a + b + ... + e using the fact that you know p + q + ... + t already.
By the way: You constantly post your question in the wrong forum. Why?
You have posted a lot of questions but never have shown any form of own work. Why?