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Finding the Fourth Proportional to 656.31, 905.90 and 390.93

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Solution

The fourth proportional to 656.31, 905.90 and 390.93 is: 539.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.31 : 905.90 = 390.93 : x
  2. Step 2: Convert to fraction form
    656.31/905.90 = 390.93/x
  3. Step 3: Cross multiply
    656.31x = 905.90 × 390.93
  4. Step 4: Simplify right side
    656.31x = 354,141.53
  5. Step 5: Solve for x
    x = 354,141.53/656.31
  6. Step 6: Final answer
    x = 539.59

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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.