Algebra-2

The missing number is 3.

 

Here's the explanation: In Pascal's Triangle, each number (except for the 1s on the edges of each row) is the sum of the two numbers directly above it in the previous row.

 

For the fourth row where the missing number is located, we look at the third row which has the numbers 1, 2, 1.

 

The number we need to find in the fourth row has the two numbers 2 and 1 directly above it from the third row. When we add 2 and 1 together (2 + 1), we get 3.

 

So the completed Pascal's Triangle would be:

               &n...