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Finding the Fourth Proportional to 66.31, 99.30 and 54.69

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Solution

The fourth proportional to 66.31, 99.30 and 54.69 is: 81.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.31 : 99.30 = 54.69 : x
  2. Step 2: Convert to fraction form
    66.31/99.30 = 54.69/x
  3. Step 3: Cross multiply
    66.31x = 99.30 × 54.69
  4. Step 4: Simplify right side
    66.31x = 5,430.72
  5. Step 5: Solve for x
    x = 5,430.72/66.31
  6. Step 6: Final answer
    x = 81.90

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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.