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Finding the Fourth Proportional to 76.78, 106 and 54.71

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Solution

The fourth proportional to 76.78, 106 and 54.71 is: 75.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    76.78 : 106 = 54.71 : x
  2. Step 2: Convert to fraction form
    76.78/106 = 54.71/x
  3. Step 3: Cross multiply
    76.78x = 106 × 54.71
  4. Step 4: Simplify right side
    76.78x = 5,799.26
  5. Step 5: Solve for x
    x = 5,799.26/76.78
  6. Step 6: Final answer
    x = 75.53

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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.