Diane is participating in a 4-day cross-country biking challenge. She biked for 57, 67, and 45 miles on the first three days. How many miles does she need to bike on the last day so that her average (mean) is 59 miles per day?

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