Based on slope, how do you know when two lines are perpendicular? A. The slope of one line must be equal to reciprocal of the other for the two to be perpendicular. B. The slope of one line must be the negative reciprocal of the other for the two to be perpendicular. C. If the slopes of the 2 lines are equal, then they are perpendicular. D. The slope of one line must be the negative of the other slope for the two to be perpendicular.

B

Step-by-step explanation:

Perpendicular lines have negative reciprocal slopes. This means they have opposite signs (negative) and their numerators and denominators are switched ( reciprocal).

For example, these slopes are perpendicular:

3/2 and -2/3

(3/2--negate--> -3/2---> reciprocal--> -2/3)

Therefore, the answer is B.  The slope of one line must be the negative reciprocal of the other for the two to be perpendicular.

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.

answer is b

step-by-step explanation: