90 POINTS- Please help with this geometry question! I have the answer because I assumed it was congruent, but I don't have the statement reasons.

A Δ DOC = 6 in²

Step-by-step explanation:

Look at the attached graph

∵ ABCD is a trapezoid with legs AB and CD

∴ AD // BC

In Δs ABC and DCB

∵ BC is a common base

→ The heights of the Δs drawn from the points A and D to the base

   BC are equal because the line joining A and D, AD is parallel to

   the base BC

∴ Their heights are equal

→ Triangles of the same base and equal heights are equal in areas

∴ A Δ ABC = A Δ DCB

∵ A Δ ABC = A Δ ABO + A Δ BOC

∵ A Δ DCB = A Δ DOC + A Δ COB

→ Equate their right sides

∴ A Δ ABO + A Δ BOC = A Δ DOC + A Δ COB

∵ A Δ BOC = A Δ COB ⇒ common triangle

∴ A Δ ABO = A Δ DOC

∵ A Δ ABO = 6 in²

∴ A Δ DOC = 6 in²

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.