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Finding the Fourth Proportional to 42.40, 63.32 and 39.28

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Solution

The fourth proportional to 42.40, 63.32 and 39.28 is: 58.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.40 : 63.32 = 39.28 : x
  2. Step 2: Convert to fraction form
    42.40/63.32 = 39.28/x
  3. Step 3: Cross multiply
    42.40x = 63.32 × 39.28
  4. Step 4: Simplify right side
    42.40x = 2,487.21
  5. Step 5: Solve for x
    x = 2,487.21/42.40
  6. Step 6: Final answer
    x = 58.66

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.