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Finding the Fourth Proportional to 31.40, 43.12 and 29.70

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Solution

The fourth proportional to 31.40, 43.12 and 29.70 is: 40.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.40 : 43.12 = 29.70 : x
  2. Step 2: Convert to fraction form
    31.40/43.12 = 29.70/x
  3. Step 3: Cross multiply
    31.40x = 43.12 × 29.70
  4. Step 4: Simplify right side
    31.40x = 1,280.66
  5. Step 5: Solve for x
    x = 1,280.66/31.40
  6. Step 6: Final answer
    x = 40.79

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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.