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Finding the Fourth Proportional to 66.60, 99.72 and 55.80

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Solution

The fourth proportional to 66.60, 99.72 and 55.80 is: 83.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.60 : 99.72 = 55.80 : x
  2. Step 2: Convert to fraction form
    66.60/99.72 = 55.80/x
  3. Step 3: Cross multiply
    66.60x = 99.72 × 55.80
  4. Step 4: Simplify right side
    66.60x = 5,564.38
  5. Step 5: Solve for x
    x = 5,564.38/66.60
  6. Step 6: Final answer
    x = 83.55

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.