Stu dent received scores of 87 and 91 on his first two exams of the grading period. what is the lowest score stu must earn on the next exam for the test average to be at least 90 for the grading period.

90 x 3 = 270

270-(87+91) = x

270-178=92

x=92

87+91+92 =270

270/3 = 90

 he needs at least a 92 

practice. practice. practice.

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.