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Finding the Fourth Proportional to 729.86, 1,007.20 and 398.28

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Solution

The fourth proportional to 729.86, 1,007.20 and 398.28 is: 549.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    729.86 : 1,007.20 = 398.28 : x
  2. Step 2: Convert to fraction form
    729.86/1,007.20 = 398.28/x
  3. Step 3: Cross multiply
    729.86x = 1,007.20 × 398.28
  4. Step 4: Simplify right side
    729.86x = 401,143.39
  5. Step 5: Solve for x
    x = 401,143.39/729.86
  6. Step 6: Final answer
    x = 549.62

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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.