Pretty easy question just stuck please help ASAP

Consider the first four terms of the sequence below. what is the 8th term of this sequence?

Which of the following is the major negative aspect of crossover designs for research studies? a. prohibitive cost b. residual effects c-subject drepout d. incomplete randomization e. large sample size required

The measures of ? 1, ? 2, and ? 3 are 40%, 12.5%, and 25% of the sum of the angle measures of the quadrilateral. find the value of x.