Finding the Third Proportional to 139,440 and 287,136

Step by Step Solution

1. Step 1: Write the proportion equation
   139,440 : 287,136 = 287,136 : x
2. Step 2: Convert to fraction form
   139,440/287,136 = 287,136/x
3. Step 3: Cross multiply
   139,440x = 287,136 × 287,136
4. Step 4: Simplify right side
   139,440x = 82,447,082,496
5. Step 5: Solve for x
   x = 82,447,082,496/139,440
6. Step 6: Final answer
   x = 591,272.82