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Finding the Fourth Proportional to 103.88, 155.42 and 86.67

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Solution

The fourth proportional to 103.88, 155.42 and 86.67 is: 129.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.88 : 155.42 = 86.67 : x
  2. Step 2: Convert to fraction form
    103.88/155.42 = 86.67/x
  3. Step 3: Cross multiply
    103.88x = 155.42 × 86.67
  4. Step 4: Simplify right side
    103.88x = 13,470.14
  5. Step 5: Solve for x
    x = 13,470.14/103.88
  6. Step 6: Final answer
    x = 129.67

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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.