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Finding the Fourth Proportional to 656.56, 905.99 and 420.09

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Solution

The fourth proportional to 656.56, 905.99 and 420.09 is: 579.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.56 : 905.99 = 420.09 : x
  2. Step 2: Convert to fraction form
    656.56/905.99 = 420.09/x
  3. Step 3: Cross multiply
    656.56x = 905.99 × 420.09
  4. Step 4: Simplify right side
    656.56x = 380,597.34
  5. Step 5: Solve for x
    x = 380,597.34/656.56
  6. Step 6: Final answer
    x = 579.68

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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.