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Finding the Fourth Proportional to 42.75, 63.81 and 39.87

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Solution

The fourth proportional to 42.75, 63.81 and 39.87 is: 59.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.75 : 63.81 = 39.87 : x
  2. Step 2: Convert to fraction form
    42.75/63.81 = 39.87/x
  3. Step 3: Cross multiply
    42.75x = 63.81 × 39.87
  4. Step 4: Simplify right side
    42.75x = 2,544.10
  5. Step 5: Solve for x
    x = 2,544.10/42.75
  6. Step 6: Final answer
    x = 59.51

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.