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Finding the Fourth Proportional to 76.11, 105.30 and 66.42

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Solution

The fourth proportional to 76.11, 105.30 and 66.42 is: 91.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.11 : 105.30 = 66.42 : x
  2. Step 2: Convert to fraction form
    76.11/105.30 = 66.42/x
  3. Step 3: Cross multiply
    76.11x = 105.30 × 66.42
  4. Step 4: Simplify right side
    76.11x = 6,994.03
  5. Step 5: Solve for x
    x = 6,994.03/76.11
  6. Step 6: Final answer
    x = 91.90

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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.