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Finding the Fourth Proportional to 674.78, 931.05 and 391.14

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Solution

The fourth proportional to 674.78, 931.05 and 391.14 is: 539.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    674.78 : 931.05 = 391.14 : x
  2. Step 2: Convert to fraction form
    674.78/931.05 = 391.14/x
  3. Step 3: Cross multiply
    674.78x = 931.05 × 391.14
  4. Step 4: Simplify right side
    674.78x = 364,170.90
  5. Step 5: Solve for x
    x = 364,170.90/674.78
  6. Step 6: Final answer
    x = 539.69

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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.