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Finding the Fourth Proportional to 1,212.60, 1,815.54 and 778.68

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Solution

The fourth proportional to 1,212.60, 1,815.54 and 778.68 is: 1,165.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.60 : 1,815.54 = 778.68 : x
  2. Step 2: Convert to fraction form
    1,212.60/1,815.54 = 778.68/x
  3. Step 3: Cross multiply
    1,212.60x = 1,815.54 × 778.68
  4. Step 4: Simplify right side
    1,212.60x = 1,413,724.69
  5. Step 5: Solve for x
    x = 1,413,724.69/1,212.60
  6. Step 6: Final answer
    x = 1,165.86

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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.