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Finding the Fourth Proportional to 918.28, 1,377.82 and 398.20

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Solution

The fourth proportional to 918.28, 1,377.82 and 398.20 is: 597.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.28 : 1,377.82 = 398.20 : x
  2. Step 2: Convert to fraction form
    918.28/1,377.82 = 398.20/x
  3. Step 3: Cross multiply
    918.28x = 1,377.82 × 398.20
  4. Step 4: Simplify right side
    918.28x = 548,647.92
  5. Step 5: Solve for x
    x = 548,647.92/918.28
  6. Step 6: Final answer
    x = 597.47

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.