Answer:
84
Step-by-step explanation:
4 test grades with an average of 80 would have a total of 80x4=320.
75+83+78=236
320-236=84
Answer:


Step-by-step explanation:





The answer is the angles are neither complementary nor supplementary, because complementary is to add up to 90° and supplementary is to add up to 180°, and these angles add up to 169°. I hope this helps!