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Finding the Fourth Proportional to 55.66, 76.78 and 39.30

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Solution

The fourth proportional to 55.66, 76.78 and 39.30 is: 54.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    55.66 : 76.78 = 39.30 : x
  2. Step 2: Convert to fraction form
    55.66/76.78 = 39.30/x
  3. Step 3: Cross multiply
    55.66x = 76.78 × 39.30
  4. Step 4: Simplify right side
    55.66x = 3,017.45
  5. Step 5: Solve for x
    x = 3,017.45/55.66
  6. Step 6: Final answer
    x = 54.21

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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.