NEED HELP FAST PLEASE!

News cameras take an overhead picture of a crowd at an outdoor event journalist then count the total number of people in the picture and use the sample of estimate the total number of people in the crowd this process is an example of

If n stands for number sold and c stands for cost per item, in which column would you use the formula: ? a. column d c. column f b. column e d. column g

Someone me what is the area of this figure? 18m 18m 8m 16m