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Finding the Fourth Proportional to 728.43, 1,005.22 and 405.03

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Solution

The fourth proportional to 728.43, 1,005.22 and 405.03 is: 558.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.43 : 1,005.22 = 405.03 : x
  2. Step 2: Convert to fraction form
    728.43/1,005.22 = 405.03/x
  3. Step 3: Cross multiply
    728.43x = 1,005.22 × 405.03
  4. Step 4: Simplify right side
    728.43x = 407,144.26
  5. Step 5: Solve for x
    x = 407,144.26/728.43
  6. Step 6: Final answer
    x = 558.93

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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.