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Finding the Fourth Proportional to 42.90, 58.82 and 39.85

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Solution

The fourth proportional to 42.90, 58.82 and 39.85 is: 54.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.90 : 58.82 = 39.85 : x
  2. Step 2: Convert to fraction form
    42.90/58.82 = 39.85/x
  3. Step 3: Cross multiply
    42.90x = 58.82 × 39.85
  4. Step 4: Simplify right side
    42.90x = 2,343.98
  5. Step 5: Solve for x
    x = 2,343.98/42.90
  6. Step 6: Final answer
    x = 54.64

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.