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Finding the Fourth Proportional to 728.40, 1,005.12 and 429.64

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Solution

The fourth proportional to 728.40, 1,005.12 and 429.64 is: 592.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.40 : 1,005.12 = 429.64 : x
  2. Step 2: Convert to fraction form
    728.40/1,005.12 = 429.64/x
  3. Step 3: Cross multiply
    728.40x = 1,005.12 × 429.64
  4. Step 4: Simplify right side
    728.40x = 431,839.76
  5. Step 5: Solve for x
    x = 431,839.76/728.40
  6. Step 6: Final answer
    x = 592.86

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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.