Using suitable identity evaluate 8.5 x 11.5​

Find the value of the variable and the length of each secant segment.

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .

∆red ≅ ∆ by rule will give brainiest if possible