Mrs. Lewis has placemats that are in the shape of trapezoids. She knows that the perimeter of each one is 50 inches.
She also knows the length of three sides: 12 inches, 12 inches, and 15 inches.
What is the length of the fourth side? Enter your answer in the box

Anew test for ra is being developed. the test is administered to 750 patients with ra and 750 without ra. for the sake of the question, assume the prevalence of ra in this population is 50%. of the 750 patients with ra, 575 have a positive result. of the 750 patients without ra, 150 have a positive result. what is the positive predictive value of the new test? a575/(575+150) b. 600/(600+ 150) c. 575/(575+125) d. 600/(600+ 125)