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Finding the Fourth Proportional to 1,212.60, 1,819.08 and 390.60

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Solution

The fourth proportional to 1,212.60, 1,819.08 and 390.60 is: 585.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.60 : 1,819.08 = 390.60 : x
  2. Step 2: Convert to fraction form
    1,212.60/1,819.08 = 390.60/x
  3. Step 3: Cross multiply
    1,212.60x = 1,819.08 × 390.60
  4. Step 4: Simplify right side
    1,212.60x = 710,532.65
  5. Step 5: Solve for x
    x = 710,532.65/1,212.60
  6. Step 6: Final answer
    x = 585.96

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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.