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Finding the Fourth Proportional to 77.87, 107.46 and 42.90

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Solution

The fourth proportional to 77.87, 107.46 and 42.90 is: 59.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.87 : 107.46 = 42.90 : x
  2. Step 2: Convert to fraction form
    77.87/107.46 = 42.90/x
  3. Step 3: Cross multiply
    77.87x = 107.46 × 42.90
  4. Step 4: Simplify right side
    77.87x = 4,609.93
  5. Step 5: Solve for x
    x = 4,609.93/77.87
  6. Step 6: Final answer
    x = 59.20

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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.