Finding the Third Proportional to 139,090 and 208,540

Step by Step Solution

1. Step 1: Write the proportion equation
   139,090 : 208,540 = 208,540 : x
2. Step 2: Convert to fraction form
   139,090/208,540 = 208,540/x
3. Step 3: Cross multiply
   139,090x = 208,540 × 208,540
4. Step 4: Simplify right side
   139,090x = 43,488,931,600
5. Step 5: Solve for x
   x = 43,488,931,600/139,090
6. Step 6: Final answer
   x = 312,667.56