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Finding the Fourth Proportional to 42.12, 58.20 and 31.77

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Solution

The fourth proportional to 42.12, 58.20 and 31.77 is: 43.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.12 : 58.20 = 31.77 : x
  2. Step 2: Convert to fraction form
    42.12/58.20 = 31.77/x
  3. Step 3: Cross multiply
    42.12x = 58.20 × 31.77
  4. Step 4: Simplify right side
    42.12x = 1,849.01
  5. Step 5: Solve for x
    x = 1,849.01/42.12
  6. Step 6: Final answer
    x = 43.90

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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.