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Finding the Fourth Proportional to 128.72, 193.04 and 56.58

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Solution

The fourth proportional to 128.72, 193.04 and 56.58 is: 84.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.72 : 193.04 = 56.58 : x
  2. Step 2: Convert to fraction form
    128.72/193.04 = 56.58/x
  3. Step 3: Cross multiply
    128.72x = 193.04 × 56.58
  4. Step 4: Simplify right side
    128.72x = 10,921.92
  5. Step 5: Solve for x
    x = 10,921.92/128.72
  6. Step 6: Final answer
    x = 84.85

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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.