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Finding the Fourth Proportional to 656.56, 905.65 and 390.82

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Solution

The fourth proportional to 656.56, 905.65 and 390.82 is: 539.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.56 : 905.65 = 390.82 : x
  2. Step 2: Convert to fraction form
    656.56/905.65 = 390.82/x
  3. Step 3: Cross multiply
    656.56x = 905.65 × 390.82
  4. Step 4: Simplify right side
    656.56x = 353,943.05
  5. Step 5: Solve for x
    x = 353,943.05/656.56
  6. Step 6: Final answer
    x = 539.09

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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.