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Finding the Fourth Proportional to 40.39, 55.70 and 31.20

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Solution

The fourth proportional to 40.39, 55.70 and 31.20 is: 43.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.39 : 55.70 = 31.20 : x
  2. Step 2: Convert to fraction form
    40.39/55.70 = 31.20/x
  3. Step 3: Cross multiply
    40.39x = 55.70 × 31.20
  4. Step 4: Simplify right side
    40.39x = 1,737.84
  5. Step 5: Solve for x
    x = 1,737.84/40.39
  6. Step 6: Final answer
    x = 43.03

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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.