Since wants needs an 85 as an average and he takes five tests, he must have 85 * 5 = <<85*5=425>>425 total points.

Currently he has 85 + 79 + 92 + 84 = <<85+79+92+84=340>>340 points.

So for his fifth test he needs 425 - 340 = <<425-340=85>>85 points.

# Answer

85
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Jacob takes four tests in his physics class and earns 85, 79, 92 and 84. What must he earn on his fifth and final test to have an overall average of 85?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
85
Jacob takes four tests in his physics class and earns 85, 79, 92 and 84. What must he earn on his fifth and final test to have an overall average of 85?
train