Finding the Third Proportional to 138,439 and 216,880.50

Step by Step Solution

1. Step 1: Write the proportion equation
   138,439 : 216,880.50 = 216,880.50 : x
2. Step 2: Convert to fraction form
   138,439/216,880.50 = 216,880.50/x
3. Step 3: Cross multiply
   138,439x = 216,880.50 × 216,880.50
4. Step 4: Simplify right side
   138,439x = 47,037,151,280.25
5. Step 5: Solve for x
   x = 47,037,151,280.25/138,439
6. Step 6: Final answer
   x = 339,768.07