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Finding the Fourth Proportional to 493.78, 740.68 and 128.57

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Solution

The fourth proportional to 493.78, 740.68 and 128.57 is: 192.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    493.78 : 740.68 = 128.57 : x
  2. Step 2: Convert to fraction form
    493.78/740.68 = 128.57/x
  3. Step 3: Cross multiply
    493.78x = 740.68 × 128.57
  4. Step 4: Simplify right side
    493.78x = 95,228.58
  5. Step 5: Solve for x
    x = 95,228.58/493.78
  6. Step 6: Final answer
    x = 192.86

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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.