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Finding the Fourth Proportional to 55.78, 76.86 and 42.64

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Solution

The fourth proportional to 55.78, 76.86 and 42.64 is: 58.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.78 : 76.86 = 42.64 : x
  2. Step 2: Convert to fraction form
    55.78/76.86 = 42.64/x
  3. Step 3: Cross multiply
    55.78x = 76.86 × 42.64
  4. Step 4: Simplify right side
    55.78x = 3,277.31
  5. Step 5: Solve for x
    x = 3,277.31/55.78
  6. Step 6: Final answer
    x = 58.75

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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.