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Finding the Fourth Proportional to 31.36, 43.12 and 30.40

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Solution

The fourth proportional to 31.36, 43.12 and 30.40 is: 41.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.36 : 43.12 = 30.40 : x
  2. Step 2: Convert to fraction form
    31.36/43.12 = 30.40/x
  3. Step 3: Cross multiply
    31.36x = 43.12 × 30.40
  4. Step 4: Simplify right side
    31.36x = 1,310.92
  5. Step 5: Solve for x
    x = 1,310.92/31.36
  6. Step 6: Final answer
    x = 41.80

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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.