Finding the Third Proportional to 128,120 and 272,870

Step by Step Solution

1. Step 1: Write the proportion equation
   128,120 : 272,870 = 272,870 : x
2. Step 2: Convert to fraction form
   128,120/272,870 = 272,870/x
3. Step 3: Cross multiply
   128,120x = 272,870 × 272,870
4. Step 4: Simplify right side
   128,120x = 74,458,036,900
5. Step 5: Solve for x
   x = 74,458,036,900/128,120
6. Step 6: Final answer
   x = 581,158.58