Finding the Third Proportional to 387,453 and 520,672.50

Step by Step Solution

1. Step 1: Write the proportion equation
   387,453 : 520,672.50 = 520,672.50 : x
2. Step 2: Convert to fraction form
   387,453/520,672.50 = 520,672.50/x
3. Step 3: Cross multiply
   387,453x = 520,672.50 × 520,672.50
4. Step 4: Simplify right side
   387,453x = 271,099,852,256.25
5. Step 5: Solve for x
   x = 271,099,852,256.25/387,453
6. Step 6: Final answer
   x = 699,697.39