Finding the Third Proportional to 139,947.75 and 306,139.50

Step by Step Solution

1. Step 1: Write the proportion equation
   139,947.75 : 306,139.50 = 306,139.50 : x
2. Step 2: Convert to fraction form
   139,947.75/306,139.50 = 306,139.50/x
3. Step 3: Cross multiply
   139,947.75x = 306,139.50 × 306,139.50
4. Step 4: Simplify right side
   139,947.75x = 93,721,393,460.25
5. Step 5: Solve for x
   x = 93,721,393,460.25/139,947.75
6. Step 6: Final answer
   x = 669,688.46