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Finding the Fourth Proportional to 55.80, 76.86 and 39.42

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Solution

The fourth proportional to 55.80, 76.86 and 39.42 is: 54.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.80 : 76.86 = 39.42 : x
  2. Step 2: Convert to fraction form
    55.80/76.86 = 39.42/x
  3. Step 3: Cross multiply
    55.80x = 76.86 × 39.42
  4. Step 4: Simplify right side
    55.80x = 3,029.82
  5. Step 5: Solve for x
    x = 3,029.82/55.80
  6. Step 6: Final answer
    x = 54.30

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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.