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Finding the Fourth Proportional to 66.78, 92.31 and 66.30

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Solution

The fourth proportional to 66.78, 92.31 and 66.30 is: 91.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.78 : 92.31 = 66.30 : x
  2. Step 2: Convert to fraction form
    66.78/92.31 = 66.30/x
  3. Step 3: Cross multiply
    66.78x = 92.31 × 66.30
  4. Step 4: Simplify right side
    66.78x = 6,120.15
  5. Step 5: Solve for x
    x = 6,120.15/66.78
  6. Step 6: Final answer
    x = 91.65

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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.