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Finding the Fourth Proportional to 1,200.62, 1,800.91 and 420.61

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Solution

The fourth proportional to 1,200.62, 1,800.91 and 420.61 is: 630.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,200.62 : 1,800.91 = 420.61 : x
  2. Step 2: Convert to fraction form
    1,200.62/1,800.91 = 420.61/x
  3. Step 3: Cross multiply
    1,200.62x = 1,800.91 × 420.61
  4. Step 4: Simplify right side
    1,200.62x = 757,477.30
  5. Step 5: Solve for x
    x = 757,477.30/1,200.62
  6. Step 6: Final answer
    x = 630.90

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.