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Finding the Fourth Proportional to 728.56, 1,090.68 and 439.12

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Solution

The fourth proportional to 728.56, 1,090.68 and 439.12 is: 657.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.56 : 1,090.68 = 439.12 : x
  2. Step 2: Convert to fraction form
    728.56/1,090.68 = 439.12/x
  3. Step 3: Cross multiply
    728.56x = 1,090.68 × 439.12
  4. Step 4: Simplify right side
    728.56x = 478,939.40
  5. Step 5: Solve for x
    x = 478,939.40/728.56
  6. Step 6: Final answer
    x = 657.38

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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.