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Finding the Fourth Proportional to 978.60, 1,468.42 and 431.16

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Solution

The fourth proportional to 978.60, 1,468.42 and 431.16 is: 646.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.60 : 1,468.42 = 431.16 : x
  2. Step 2: Convert to fraction form
    978.60/1,468.42 = 431.16/x
  3. Step 3: Cross multiply
    978.60x = 1,468.42 × 431.16
  4. Step 4: Simplify right side
    978.60x = 633,121.81
  5. Step 5: Solve for x
    x = 633,121.81/978.60
  6. Step 6: Final answer
    x = 646.97

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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.