Finding the Third Proportional to 258,030 and 390,936

Step by Step Solution

1. Step 1: Write the proportion equation
   258,030 : 390,936 = 390,936 : x
2. Step 2: Convert to fraction form
   258,030/390,936 = 390,936/x
3. Step 3: Cross multiply
   258,030x = 390,936 × 390,936
4. Step 4: Simplify right side
   258,030x = 152,830,956,096
5. Step 5: Solve for x
   x = 152,830,956,096/258,030
6. Step 6: Final answer
   x = 592,299.17