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Finding the Fourth Proportional to 1,018.17, 1,403.41 and 840.78

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Solution

The fourth proportional to 1,018.17, 1,403.41 and 840.78 is: 1,158.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,018.17 : 1,403.41 = 840.78 : x
  2. Step 2: Convert to fraction form
    1,018.17/1,403.41 = 840.78/x
  3. Step 3: Cross multiply
    1,018.17x = 1,403.41 × 840.78
  4. Step 4: Simplify right side
    1,018.17x = 1,179,959.06
  5. Step 5: Solve for x
    x = 1,179,959.06/1,018.17
  6. Step 6: Final answer
    x = 1,158.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.