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Finding the Fourth Proportional to 42.58, 58.71 and 28.74

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Solution

The fourth proportional to 42.58, 58.71 and 28.74 is: 39.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.58 : 58.71 = 28.74 : x
  2. Step 2: Convert to fraction form
    42.58/58.71 = 28.74/x
  3. Step 3: Cross multiply
    42.58x = 58.71 × 28.74
  4. Step 4: Simplify right side
    42.58x = 1,687.16
  5. Step 5: Solve for x
    x = 1,687.16/42.58
  6. Step 6: Final answer
    x = 39.63

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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.