A page of two-dimensional arrays can be thought of as a three-dimensional array. Since 2-dimensional arrays are commonly expressed in tables or matrixes, therefore, if we put these tables or matrices in a page, the collection of matrices in a single page would now be structured into a 3D array.
The average value of a data set is equal to the sum of each entry divided by the number of entries. In this case, we have 5 scores, so we can find set up the following equation where x is the fifth score: