Finding the Third Proportional to 391,264 and 813,140

Step by Step Solution

1. Step 1: Write the proportion equation
   391,264 : 813,140 = 813,140 : x
2. Step 2: Convert to fraction form
   391,264/813,140 = 813,140/x
3. Step 3: Cross multiply
   391,264x = 813,140 × 813,140
4. Step 4: Simplify right side
   391,264x = 661,196,659,600
5. Step 5: Solve for x
   x = 661,196,659,600/391,264
6. Step 6: Final answer
   x = 1,689,899.04