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Finding the Fourth Proportional to 93.10, 128.42 and 76.70

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Solution

The fourth proportional to 93.10, 128.42 and 76.70 is: 105.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.10 : 128.42 = 76.70 : x
  2. Step 2: Convert to fraction form
    93.10/128.42 = 76.70/x
  3. Step 3: Cross multiply
    93.10x = 128.42 × 76.70
  4. Step 4: Simplify right side
    93.10x = 9,849.43
  5. Step 5: Solve for x
    x = 9,849.43/93.10
  6. Step 6: Final answer
    x = 105.79

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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.