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Finding the Fourth Proportional to 10.40, 14.38 and 9.90

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Solution

The fourth proportional to 10.40, 14.38 and 9.90 is: 13.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.40 : 14.38 = 9.90 : x
  2. Step 2: Convert to fraction form
    10.40/14.38 = 9.90/x
  3. Step 3: Cross multiply
    10.40x = 14.38 × 9.90
  4. Step 4: Simplify right side
    10.40x = 142.36
  5. Step 5: Solve for x
    x = 142.36/10.40
  6. Step 6: Final answer
    x = 13.69

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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.