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Finding the Fourth Proportional to 978.89, 1,468.68 and 431.00

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Solution

The fourth proportional to 978.89, 1,468.68 and 431.00 is: 646.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.89 : 1,468.68 = 431.00 : x
  2. Step 2: Convert to fraction form
    978.89/1,468.68 = 431.00/x
  3. Step 3: Cross multiply
    978.89x = 1,468.68 × 431.00
  4. Step 4: Simplify right side
    978.89x = 632,991.58
  5. Step 5: Solve for x
    x = 632,991.58/978.89
  6. Step 6: Final answer
    x = 646.65

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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.