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Finding the Fourth Proportional to 40.31, 55.46 and 39.40

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Solution

The fourth proportional to 40.31, 55.46 and 39.40 is: 54.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.31 : 55.46 = 39.40 : x
  2. Step 2: Convert to fraction form
    40.31/55.46 = 39.40/x
  3. Step 3: Cross multiply
    40.31x = 55.46 × 39.40
  4. Step 4: Simplify right side
    40.31x = 2,185.12
  5. Step 5: Solve for x
    x = 2,185.12/40.31
  6. Step 6: Final answer
    x = 54.21

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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.