The mean of n numbers is the sum of the numbers divided by n.
You have a mean score of 84 after taking 5 tests. Let x be the sum of scores.

You scored a total of 420 points on five tests.
You need to have a mean score of 85 after taking 6 tests. Let y be the score you need to obtain. Your total score on 6 tests is 420+y.

You need to score 90 points on the sixth test.
Using the tangent rule:
Tangent(angle) = Opposite leg / Adjacent leg
We will use the 23 degree angle to solve for x.
Tangent(23) = X / 6
x = 6 * tangent(23)
x = 2.5
Its an area equation. Area is length times width.
So to start, he needs 50x80 square feet in his front yard, BUT THAT IS ONLY HALF OF THE PROBLEM. For the front yard he needs 4000 sq. feet. For the back, it is different. He needs 10x40÷2. To first simplify, we do the multiplication. This comes to 400÷2. then it is simply 200.
Now for the easy part. Take the 4000 and add 200. Answer? 4,200.
Answer:
Divided by 10 every time
Step-by-step explanation:
/10 is the pattern