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Finding the Fourth Proportional to 66.89, 99.85 and 57.20

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Solution

The fourth proportional to 66.89, 99.85 and 57.20 is: 85.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.89 : 99.85 = 57.20 : x
  2. Step 2: Convert to fraction form
    66.89/99.85 = 57.20/x
  3. Step 3: Cross multiply
    66.89x = 99.85 × 57.20
  4. Step 4: Simplify right side
    66.89x = 5,711.42
  5. Step 5: Solve for x
    x = 5,711.42/66.89
  6. Step 6: Final answer
    x = 85.39

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.