Finding the Fourth Proportional to 19,978.19, 29,967.30 and 5,185.87

Step by Step Solution

1. Step 1: Write the proportion equation
   19,978.19 : 29,967.30 = 5,185.87 : x
2. Step 2: Convert to fraction form
   19,978.19/29,967.30 = 5,185.87/x
3. Step 3: Cross multiply
   19,978.19x = 29,967.30 × 5,185.87
4. Step 4: Simplify right side
   19,978.19x = 155,406,447.13
5. Step 5: Solve for x
   x = 155,406,447.13/19,978.19
6. Step 6: Final answer
   x = 7,778.81