Finding the Fourth Proportional to 318,685.71, 478,499.69 and 212,729.81

Step by Step Solution

1. Step 1: Write the proportion equation
   318,685.71 : 478,499.69 = 212,729.81 : x
2. Step 2: Convert to fraction form
   318,685.71/478,499.69 = 212,729.81/x
3. Step 3: Cross multiply
   318,685.71x = 478,499.69 × 212,729.81
4. Step 4: Simplify right side
   318,685.71x = 101,791,147,773.04
5. Step 5: Solve for x
   x = 101,791,147,773.04/318,685.71
6. Step 6: Final answer
   x = 319,409.20