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Finding the Fourth Proportional to 1,212.80, 1,819.29 and 391.05

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Solution

The fourth proportional to 1,212.80, 1,819.29 and 391.05 is: 586.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.80 : 1,819.29 = 391.05 : x
  2. Step 2: Convert to fraction form
    1,212.80/1,819.29 = 391.05/x
  3. Step 3: Cross multiply
    1,212.80x = 1,819.29 × 391.05
  4. Step 4: Simplify right side
    1,212.80x = 711,433.35
  5. Step 5: Solve for x
    x = 711,433.35/1,212.80
  6. Step 6: Final answer
    x = 586.61

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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.