Finding the Third Proportional to 390,070 and 620,632.50

Step by Step Solution

1. Step 1: Write the proportion equation
   390,070 : 620,632.50 = 620,632.50 : x
2. Step 2: Convert to fraction form
   390,070/620,632.50 = 620,632.50/x
3. Step 3: Cross multiply
   390,070x = 620,632.50 × 620,632.50
4. Step 4: Simplify right side
   390,070x = 385,184,700,056.25
5. Step 5: Solve for x
   x = 385,184,700,056.25/390,070
6. Step 6: Final answer
   x = 987,475.84