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Finding the Fourth Proportional to 978.15, 1,349.87 and 585.39

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Solution

The fourth proportional to 978.15, 1,349.87 and 585.39 is: 807.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.15 : 1,349.87 = 585.39 : x
  2. Step 2: Convert to fraction form
    978.15/1,349.87 = 585.39/x
  3. Step 3: Cross multiply
    978.15x = 1,349.87 × 585.39
  4. Step 4: Simplify right side
    978.15x = 790,200.85
  5. Step 5: Solve for x
    x = 790,200.85/978.15
  6. Step 6: Final answer
    x = 807.86

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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.