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Finding the Fourth Proportional to 266.20, 399.35 and 81.11

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Solution

The fourth proportional to 266.20, 399.35 and 81.11 is: 121.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    266.20 : 399.35 = 81.11 : x
  2. Step 2: Convert to fraction form
    266.20/399.35 = 81.11/x
  3. Step 3: Cross multiply
    266.20x = 399.35 × 81.11
  4. Step 4: Simplify right side
    266.20x = 32,390.39
  5. Step 5: Solve for x
    x = 32,390.39/266.20
  6. Step 6: Final answer
    x = 121.68

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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.