The teacher probably wants you to multiply cause area refers to that

get rid of -2 by subtracting it from 21

Now you get your answer

Hope this helps! :)
Answer:16
Step-by-step explanation:
Area of a triangle = (height * base ) / 2
height = (Area * 2) / base
height = (49.5 * 2) / 9
height = 99 / 9
height = 10 cm²
We can plot this data on MS Excel and determine the distribution of these data reflected on the graph. Among these numbers, 50 is the outlier since it is very far from the other numbers ranging from 76 to 83. We can perform interquartile range to determine or verify the outliers in the data set. In this respect, we can see that there is not much distribution seen. The average of all data sets is equal to 96.25. When the outlier (50) is removed, we expect the mean to become higher since a low number was ommitted including high numbers only. Outliers are obtained from special causations such as human errors.