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Finding the Fourth Proportional to 656.56, 905.74 and 420.39

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Solution

The fourth proportional to 656.56, 905.74 and 420.39 is: 579.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.56 : 905.74 = 420.39 : x
  2. Step 2: Convert to fraction form
    656.56/905.74 = 420.39/x
  3. Step 3: Cross multiply
    656.56x = 905.74 × 420.39
  4. Step 4: Simplify right side
    656.56x = 380,764.04
  5. Step 5: Solve for x
    x = 380,764.04/656.56
  6. Step 6: Final answer
    x = 579.94

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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.