Finding the Third Proportional to 218,064 and 309,240

Step by Step Solution

1. Step 1: Write the proportion equation
   218,064 : 309,240 = 309,240 : x
2. Step 2: Convert to fraction form
   218,064/309,240 = 309,240/x
3. Step 3: Cross multiply
   218,064x = 309,240 × 309,240
4. Step 4: Simplify right side
   218,064x = 95,629,377,600
5. Step 5: Solve for x
   x = 95,629,377,600/218,064
6. Step 6: Final answer
   x = 438,538.12