the pentagon has 3 angles which are each 140°. The other two interior angles are equal. calculate the size of one of these angles

60°

Step-by-step explanation:

The sum of the interior angles of a polygon is

sum = 180° (n - 2) ← n is the number of sides

Here n = 5 ( pentagon ), thus

sum = 180° × 3 = 540°

let x be the size of the equal angles

Sum the interior angles and equate to 540

(3 × 140 ) + 2x = 540

420 + 2x = 540 ( subtract 240 from both sides )

2x = 120 ( divide both sides by 2 )

x = 60

Thus the size of 1 of the 2 equal angles = 60°

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.