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Finding the Fourth Proportional to 728.56, 1,086.69 and 611.64

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Solution

The fourth proportional to 728.56, 1,086.69 and 611.64 is: 912.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.56 : 1,086.69 = 611.64 : x
  2. Step 2: Convert to fraction form
    728.56/1,086.69 = 611.64/x
  3. Step 3: Cross multiply
    728.56x = 1,086.69 × 611.64
  4. Step 4: Simplify right side
    728.56x = 664,663.07
  5. Step 5: Solve for x
    x = 664,663.07/728.56
  6. Step 6: Final answer
    x = 912.30

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.