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Finding the Fourth Proportional to 66.30, 91.89 and 65.55

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Solution

The fourth proportional to 66.30, 91.89 and 65.55 is: 90.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.30 : 91.89 = 65.55 : x
  2. Step 2: Convert to fraction form
    66.30/91.89 = 65.55/x
  3. Step 3: Cross multiply
    66.30x = 91.89 × 65.55
  4. Step 4: Simplify right side
    66.30x = 6,023.39
  5. Step 5: Solve for x
    x = 6,023.39/66.30
  6. Step 6: Final answer
    x = 90.85

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.