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Finding the Fourth Proportional to 656.20, 905.64 and 420.16

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Solution

The fourth proportional to 656.20, 905.64 and 420.16 is: 579.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    656.20 : 905.64 = 420.16 : x
  2. Step 2: Convert to fraction form
    656.20/905.64 = 420.16/x
  3. Step 3: Cross multiply
    656.20x = 905.64 × 420.16
  4. Step 4: Simplify right side
    656.20x = 380,513.70
  5. Step 5: Solve for x
    x = 380,513.70/656.20
  6. Step 6: Final answer
    x = 579.87

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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.