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Finding the Fourth Proportional to 928.91, 1,391.39 and 488.78

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Solution

The fourth proportional to 928.91, 1,391.39 and 488.78 is: 732.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    928.91 : 1,391.39 = 488.78 : x
  2. Step 2: Convert to fraction form
    928.91/1,391.39 = 488.78/x
  3. Step 3: Cross multiply
    928.91x = 1,391.39 × 488.78
  4. Step 4: Simplify right side
    928.91x = 680,074.20
  5. Step 5: Solve for x
    x = 680,074.20/928.91
  6. Step 6: Final answer
    x = 732.12

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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.