Finding the Fourth Proportional to 208,139, 287,231.28 and 112,645.67

Step by Step Solution

1. Step 1: Write the proportion equation
   208,139 : 287,231.28 = 112,645.67 : x
2. Step 2: Convert to fraction form
   208,139/287,231.28 = 112,645.67/x
3. Step 3: Cross multiply
   208,139x = 287,231.28 × 112,645.67
4. Step 4: Simplify right side
   208,139x = 32,355,359,980.56
5. Step 5: Solve for x
   x = 32,355,359,980.56/208,139
6. Step 6: Final answer
   x = 155,450.73