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Finding the Fourth Proportional to 66.78, 99.91 and 57.56

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Solution

The fourth proportional to 66.78, 99.91 and 57.56 is: 86.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.78 : 99.91 = 57.56 : x
  2. Step 2: Convert to fraction form
    66.78/99.91 = 57.56/x
  3. Step 3: Cross multiply
    66.78x = 99.91 × 57.56
  4. Step 4: Simplify right side
    66.78x = 5,750.93
  5. Step 5: Solve for x
    x = 5,750.93/66.78
  6. Step 6: Final answer
    x = 86.12

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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.