Finding the Fourth Proportional to 153,688.50, 212,096.61 and 86,620.50

Step by Step Solution

1. Step 1: Write the proportion equation
   153,688.50 : 212,096.61 = 86,620.50 : x
2. Step 2: Convert to fraction form
   153,688.50/212,096.61 = 86,620.50/x
3. Step 3: Cross multiply
   153,688.50x = 212,096.61 × 86,620.50
4. Step 4: Simplify right side
   153,688.50x = 18,371,914,406.51
5. Step 5: Solve for x
   x = 18,371,914,406.51/153,688.50
6. Step 6: Final answer
   x = 119,539.94