Will mark Brainliest. So Im trying to calculate what I need to get on the final to keep an overall 80% for my semester grade. My math teacher said our final grade is 40% of 3st quarter & 40% of 4th quarter with our final weighing 20%. So what I was wondering was if i had a 85.29 in 3rd quarter and a 81.5 in 4th quarter what could i get on my final to keep an overall 80% average for my semester grade. ( my semester grade is currently at 83.39 )