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Finding the Fourth Proportional to 42.81, 64.10 and 31.29

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Solution

The fourth proportional to 42.81, 64.10 and 31.29 is: 46.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.81 : 64.10 = 31.29 : x
  2. Step 2: Convert to fraction form
    42.81/64.10 = 31.29/x
  3. Step 3: Cross multiply
    42.81x = 64.10 × 31.29
  4. Step 4: Simplify right side
    42.81x = 2,005.53
  5. Step 5: Solve for x
    x = 2,005.53/42.81
  6. Step 6: Final answer
    x = 46.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.