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Finding the Fourth Proportional to 978.48, 1,465.90 and 491.87

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Solution

The fourth proportional to 978.48, 1,465.90 and 491.87 is: 736.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    978.48 : 1,465.90 = 491.87 : x
  2. Step 2: Convert to fraction form
    978.48/1,465.90 = 491.87/x
  3. Step 3: Cross multiply
    978.48x = 1,465.90 × 491.87
  4. Step 4: Simplify right side
    978.48x = 721,034.67
  5. Step 5: Solve for x
    x = 721,034.67/978.48
  6. Step 6: Final answer
    x = 736.89

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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.