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Finding the Fourth Proportional to 42.81, 58.96 and 39.87

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Solution

The fourth proportional to 42.81, 58.96 and 39.87 is: 54.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.81 : 58.96 = 39.87 : x
  2. Step 2: Convert to fraction form
    42.81/58.96 = 39.87/x
  3. Step 3: Cross multiply
    42.81x = 58.96 × 39.87
  4. Step 4: Simplify right side
    42.81x = 2,350.79
  5. Step 5: Solve for x
    x = 2,350.79/42.81
  6. Step 6: Final answer
    x = 54.92

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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.