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Finding the Fourth Proportional to 978.14, 1,349.80 and 579.79

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Solution

The fourth proportional to 978.14, 1,349.80 and 579.79 is: 800.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.14 : 1,349.80 = 579.79 : x
  2. Step 2: Convert to fraction form
    978.14/1,349.80 = 579.79/x
  3. Step 3: Cross multiply
    978.14x = 1,349.80 × 579.79
  4. Step 4: Simplify right side
    978.14x = 782,600.78
  5. Step 5: Solve for x
    x = 782,600.78/978.14
  6. Step 6: Final answer
    x = 800.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.