Finding the Fourth Proportional to 7,978.50, 11,970.59 and 5,783.40

Step by Step Solution

1. Step 1: Write the proportion equation
   7,978.50 : 11,970.59 = 5,783.40 : x
2. Step 2: Convert to fraction form
   7,978.50/11,970.59 = 5,783.40/x
3. Step 3: Cross multiply
   7,978.50x = 11,970.59 × 5,783.40
4. Step 4: Simplify right side
   7,978.50x = 69,230,681.29
5. Step 5: Solve for x
   x = 69,230,681.29/7,978.50
6. Step 6: Final answer
   x = 8,677.16