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Finding the Fourth Proportional to 103.89, 143.40 and 87.49

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Solution

The fourth proportional to 103.89, 143.40 and 87.49 is: 120.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.89 : 143.40 = 87.49 : x
  2. Step 2: Convert to fraction form
    103.89/143.40 = 87.49/x
  3. Step 3: Cross multiply
    103.89x = 143.40 × 87.49
  4. Step 4: Simplify right side
    103.89x = 12,546.07
  5. Step 5: Solve for x
    x = 12,546.07/103.89
  6. Step 6: Final answer
    x = 120.76

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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.