Finding the Fourth Proportional to 209,131.24, 311,483.09 and 208,111.72

Step by Step Solution

1. Step 1: Write the proportion equation
   209,131.24 : 311,483.09 = 208,111.72 : x
2. Step 2: Convert to fraction form
   209,131.24/311,483.09 = 208,111.72/x
3. Step 3: Cross multiply
   209,131.24x = 311,483.09 × 208,111.72
4. Step 4: Simplify right side
   209,131.24x = 64,823,281,610.81
5. Step 5: Solve for x
   x = 64,823,281,610.81/209,131.24
6. Step 6: Final answer
   x = 309,964.60