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Finding the Fourth Proportional to 645.48, 890.28 and 558

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Solution

The fourth proportional to 645.48, 890.28 and 558 is: 769.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.48 : 890.28 = 558 : x
  2. Step 2: Convert to fraction form
    645.48/890.28 = 558/x
  3. Step 3: Cross multiply
    645.48x = 890.28 × 558
  4. Step 4: Simplify right side
    645.48x = 496,776.24
  5. Step 5: Solve for x
    x = 496,776.24/645.48
  6. Step 6: Final answer
    x = 769.62

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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.