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Finding the Fourth Proportional to 40.40, 55.81 and 31.21

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Solution

The fourth proportional to 40.40, 55.81 and 31.21 is: 43.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.40 : 55.81 = 31.21 : x
  2. Step 2: Convert to fraction form
    40.40/55.81 = 31.21/x
  3. Step 3: Cross multiply
    40.40x = 55.81 × 31.21
  4. Step 4: Simplify right side
    40.40x = 1,741.97
  5. Step 5: Solve for x
    x = 1,741.97/40.40
  6. Step 6: Final answer
    x = 43.12

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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.