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Finding the Fourth Proportional to 93.78, 129.35 and 71.91

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Solution

The fourth proportional to 93.78, 129.35 and 71.91 is: 99.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    93.78 : 129.35 = 71.91 : x
  2. Step 2: Convert to fraction form
    93.78/129.35 = 71.91/x
  3. Step 3: Cross multiply
    93.78x = 129.35 × 71.91
  4. Step 4: Simplify right side
    93.78x = 9,301.56
  5. Step 5: Solve for x
    x = 9,301.56/93.78
  6. Step 6: Final answer
    x = 99.18

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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.