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Finding the Fourth Proportional to 88.20, 121.77 and 66.42

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Solution

The fourth proportional to 88.20, 121.77 and 66.42 is: 91.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    88.20 : 121.77 = 66.42 : x
  2. Step 2: Convert to fraction form
    88.20/121.77 = 66.42/x
  3. Step 3: Cross multiply
    88.20x = 121.77 × 66.42
  4. Step 4: Simplify right side
    88.20x = 8,087.96
  5. Step 5: Solve for x
    x = 8,087.96/88.20
  6. Step 6: Final answer
    x = 91.70

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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.