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Finding the Fourth Proportional to 728.55, 1,091.85 and 398.70

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Solution

The fourth proportional to 728.55, 1,091.85 and 398.70 is: 597.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.55 : 1,091.85 = 398.70 : x
  2. Step 2: Convert to fraction form
    728.55/1,091.85 = 398.70/x
  3. Step 3: Cross multiply
    728.55x = 1,091.85 × 398.70
  4. Step 4: Simplify right side
    728.55x = 435,320.60
  5. Step 5: Solve for x
    x = 435,320.60/728.55
  6. Step 6: Final answer
    x = 597.52

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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.