Ihave a 62,75,90 on my history exams what do i need on the fourth one to have a mean of 80

Mean of the 5 is the average
lets solve for what score gets 80
and lets say last score is x

so

(sum of scores)/4=80
(62+75+90+x)/4=80
(227+x)/4=80
times 4 both sides
227+x=320
minus 227 from both sides
x=93
yo need a 93
good luck

Answer: r=4.5  feetexplanation: radius  r  is half of the diameter  d,⇒r=d2=92=4.5  feetidk i could be wrong

Ican't do any of the other stuff, but i can get you started. the answer, i believe, is $2.50.