Finding the Fourth Proportional to 19,978.56, 29,967.90 and 5,187.60

Step by Step Solution

1. Step 1: Write the proportion equation
   19,978.56 : 29,967.90 = 5,187.60 : x
2. Step 2: Convert to fraction form
   19,978.56/29,967.90 = 5,187.60/x
3. Step 3: Cross multiply
   19,978.56x = 29,967.90 × 5,187.60
4. Step 4: Simplify right side
   19,978.56x = 155,461,458.59
5. Step 5: Solve for x
   x = 155,461,458.59/19,978.56
6. Step 6: Final answer
   x = 7,781.41