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Finding the Fourth Proportional to 66.81, 91.89 and 58.61

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Solution

The fourth proportional to 66.81, 91.89 and 58.61 is: 80.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.81 : 91.89 = 58.61 : x
  2. Step 2: Convert to fraction form
    66.81/91.89 = 58.61/x
  3. Step 3: Cross multiply
    66.81x = 91.89 × 58.61
  4. Step 4: Simplify right side
    66.81x = 5,385.67
  5. Step 5: Solve for x
    x = 5,385.67/66.81
  6. Step 6: Final answer
    x = 80.61

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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.