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Finding the Fourth Proportional to 1,209.60, 1,814.40 and 387.90

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Solution

The fourth proportional to 1,209.60, 1,814.40 and 387.90 is: 581.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,209.60 : 1,814.40 = 387.90 : x
  2. Step 2: Convert to fraction form
    1,209.60/1,814.40 = 387.90/x
  3. Step 3: Cross multiply
    1,209.60x = 1,814.40 × 387.90
  4. Step 4: Simplify right side
    1,209.60x = 703,805.76
  5. Step 5: Solve for x
    x = 703,805.76/1,209.60
  6. Step 6: Final answer
    x = 581.85

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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.