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Finding the Fourth Proportional to 102.80, 154.20 and 66.89

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Solution

The fourth proportional to 102.80, 154.20 and 66.89 is: 100.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.80 : 154.20 = 66.89 : x
  2. Step 2: Convert to fraction form
    102.80/154.20 = 66.89/x
  3. Step 3: Cross multiply
    102.80x = 154.20 × 66.89
  4. Step 4: Simplify right side
    102.80x = 10,314.44
  5. Step 5: Solve for x
    x = 10,314.44/102.80
  6. Step 6: Final answer
    x = 100.34

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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.