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Finding the Fourth Proportional to 93.38, 128.75 and 76.72

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Solution

The fourth proportional to 93.38, 128.75 and 76.72 is: 105.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.38 : 128.75 = 76.72 : x
  2. Step 2: Convert to fraction form
    93.38/128.75 = 76.72/x
  3. Step 3: Cross multiply
    93.38x = 128.75 × 76.72
  4. Step 4: Simplify right side
    93.38x = 9,877.70
  5. Step 5: Solve for x
    x = 9,877.70/93.38
  6. Step 6: Final answer
    x = 105.78

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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.