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Finding the Fourth Proportional to 103.76, 143.03 and 85.31

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Solution

The fourth proportional to 103.76, 143.03 and 85.31 is: 117.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.76 : 143.03 = 85.31 : x
  2. Step 2: Convert to fraction form
    103.76/143.03 = 85.31/x
  3. Step 3: Cross multiply
    103.76x = 143.03 × 85.31
  4. Step 4: Simplify right side
    103.76x = 12,201.39
  5. Step 5: Solve for x
    x = 12,201.39/103.76
  6. Step 6: Final answer
    x = 117.60

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.