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Finding the Fourth Proportional to 978.87, 1,467.31 and 613.91

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Solution

The fourth proportional to 978.87, 1,467.31 and 613.91 is: 920.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.87 : 1,467.31 = 613.91 : x
  2. Step 2: Convert to fraction form
    978.87/1,467.31 = 613.91/x
  3. Step 3: Cross multiply
    978.87x = 1,467.31 × 613.91
  4. Step 4: Simplify right side
    978.87x = 900,791.08
  5. Step 5: Solve for x
    x = 900,791.08/978.87
  6. Step 6: Final answer
    x = 920.24

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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.