Finding the Third Proportional to 212,818.50 and 435,478.50

Step by Step Solution

1. Step 1: Write the proportion equation
   212,818.50 : 435,478.50 = 435,478.50 : x
2. Step 2: Convert to fraction form
   212,818.50/435,478.50 = 435,478.50/x
3. Step 3: Cross multiply
   212,818.50x = 435,478.50 × 435,478.50
4. Step 4: Simplify right side
   212,818.50x = 189,641,523,962.25
5. Step 5: Solve for x
   x = 189,641,523,962.25/212,818.50
6. Step 6: Final answer
   x = 891,095.11