Finding the Third Proportional to 390,120 and 612,136.50

Step by Step Solution

1. Step 1: Write the proportion equation
   390,120 : 612,136.50 = 612,136.50 : x
2. Step 2: Convert to fraction form
   390,120/612,136.50 = 612,136.50/x
3. Step 3: Cross multiply
   390,120x = 612,136.50 × 612,136.50
4. Step 4: Simplify right side
   390,120x = 374,711,094,632.25
5. Step 5: Solve for x
   x = 374,711,094,632.25/390,120
6. Step 6: Final answer
   x = 960,502.14