Nigel wants to average 85% on his four tests. He got 77%, 89%, 78% on his first three tests. What does he need to get on his last test to average 85%?

Step-by-step explanation:

Let x be the value of the test score needed to get 85

Equation

(77 + 89 + 78 + x)/4 = 85                Combine the left side to like terms

(244 + x)/4 = 85                              Multiply by 4

244 + x = 85 * 4

244 + x = 340                                 Subtract 244

x = 340 - 244

x = 96

He needs to get 96 to average out to 85

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.