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Finding the Fourth Proportional to 728.86, 1,005.82 and 397.28

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Solution

The fourth proportional to 728.86, 1,005.82 and 397.28 is: 548.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.86 : 1,005.82 = 397.28 : x
  2. Step 2: Convert to fraction form
    728.86/1,005.82 = 397.28/x
  3. Step 3: Cross multiply
    728.86x = 1,005.82 × 397.28
  4. Step 4: Simplify right side
    728.86x = 399,597.81
  5. Step 5: Solve for x
    x = 399,597.81/728.86
  6. Step 6: Final answer
    x = 548.25

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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.