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Finding the Fourth Proportional to 65.66, 90.40 and 55.80

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Solution

The fourth proportional to 65.66, 90.40 and 55.80 is: 76.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    65.66 : 90.40 = 55.80 : x
  2. Step 2: Convert to fraction form
    65.66/90.40 = 55.80/x
  3. Step 3: Cross multiply
    65.66x = 90.40 × 55.80
  4. Step 4: Simplify right side
    65.66x = 5,044.18
  5. Step 5: Solve for x
    x = 5,044.18/65.66
  6. Step 6: Final answer
    x = 76.83

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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.