Finding the Fourth Proportional to 16,779.69, 23,121.86 and 12,979.78

Step by Step Solution

1. Step 1: Write the proportion equation
   16,779.69 : 23,121.86 = 12,979.78 : x
2. Step 2: Convert to fraction form
   16,779.69/23,121.86 = 12,979.78/x
3. Step 3: Cross multiply
   16,779.69x = 23,121.86 × 12,979.78
4. Step 4: Simplify right side
   16,779.69x = 300,116,533.29
5. Step 5: Solve for x
   x = 300,116,533.29/16,779.69
6. Step 6: Final answer
   x = 17,885.70