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Finding the Fourth Proportional to 104.20, 143.47 and 87.79

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Solution

The fourth proportional to 104.20, 143.47 and 87.79 is: 120.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    104.20 : 143.47 = 87.79 : x
  2. Step 2: Convert to fraction form
    104.20/143.47 = 87.79/x
  3. Step 3: Cross multiply
    104.20x = 143.47 × 87.79
  4. Step 4: Simplify right side
    104.20x = 12,595.23
  5. Step 5: Solve for x
    x = 12,595.23/104.20
  6. Step 6: Final answer
    x = 120.88

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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.