How many triangles can be made if one angle is 95° and the other angle is obtuse?

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

Jack did 3/5 of all problems on his weekend homework before sunday. on sunday he solved 1/3 of what was left and the last 4 problems. how many problems were assigned for the weekend?

What is the area of the original rectangle? 8 cm² 20 cm² 25 cm² 40 cm²