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Finding the Fourth Proportional to 102.90, 154.14 and 66.86

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Solution

The fourth proportional to 102.90, 154.14 and 66.86 is: 100.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.90 : 154.14 = 66.86 : x
  2. Step 2: Convert to fraction form
    102.90/154.14 = 66.86/x
  3. Step 3: Cross multiply
    102.90x = 154.14 × 66.86
  4. Step 4: Simplify right side
    102.90x = 10,305.03
  5. Step 5: Solve for x
    x = 10,305.03/102.90
  6. Step 6: Final answer
    x = 100.15

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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.