Finding the Fourth Proportional to 12,379.79, 17,086.62 and 8,402.18

Step by Step Solution

1. Step 1: Write the proportion equation
   12,379.79 : 17,086.62 = 8,402.18 : x
2. Step 2: Convert to fraction form
   12,379.79/17,086.62 = 8,402.18/x
3. Step 3: Cross multiply
   12,379.79x = 17,086.62 × 8,402.18
4. Step 4: Simplify right side
   12,379.79x = 143,564,875.39
5. Step 5: Solve for x
   x = 143,564,875.39/12,379.79
6. Step 6: Final answer
   x = 11,596.72