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Finding the Fourth Proportional to 42.12, 58.05 and 31.19

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Solution

The fourth proportional to 42.12, 58.05 and 31.19 is: 42.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.12 : 58.05 = 31.19 : x
  2. Step 2: Convert to fraction form
    42.12/58.05 = 31.19/x
  3. Step 3: Cross multiply
    42.12x = 58.05 × 31.19
  4. Step 4: Simplify right side
    42.12x = 1,810.29
  5. Step 5: Solve for x
    x = 1,810.29/42.12
  6. Step 6: Final answer
    x = 42.98

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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.