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Finding the Fourth Proportional to 102.78, 154.23 and 85.23

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Solution

The fourth proportional to 102.78, 154.23 and 85.23 is: 127.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.78 : 154.23 = 85.23 : x
  2. Step 2: Convert to fraction form
    102.78/154.23 = 85.23/x
  3. Step 3: Cross multiply
    102.78x = 154.23 × 85.23
  4. Step 4: Simplify right side
    102.78x = 13,145.02
  5. Step 5: Solve for x
    x = 13,145.02/102.78
  6. Step 6: Final answer
    x = 127.89

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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.