Algebra-2

The correct answer is 4.

Here's how we can figure it out: In Pascal's Triangle, every number (except the 1s on the outermost edges of each row) is the sum of the two numbers directly above it in the previous row.

 

For the fifth row where the missing number (the one we need to fill in) is located, we look at the fourth row which consists of the numbers 1, 3, 3, 1.

 

The number we are trying to find in the fifth row has the two numbers 3 and 1 directly above it from the fourth row. When we add 3 and 1 together (3 + 1), we get 4.

 

So the completed Pascal's Triangle with the missing number filled in is: