Finding the Third Proportional to 390,915 and 856,633.50

Step by Step Solution

1. Step 1: Write the proportion equation
   390,915 : 856,633.50 = 856,633.50 : x
2. Step 2: Convert to fraction form
   390,915/856,633.50 = 856,633.50/x
3. Step 3: Cross multiply
   390,915x = 856,633.50 × 856,633.50
4. Step 4: Simplify right side
   390,915x = 733,820,953,322.25
5. Step 5: Solve for x
   x = 733,820,953,322.25/390,915
6. Step 6: Final answer
   x = 1,877,188.02