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Finding the Fourth Proportional to 10.40, 14.31 and 8.57

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Solution

The fourth proportional to 10.40, 14.31 and 8.57 is: 11.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.40 : 14.31 = 8.57 : x
  2. Step 2: Convert to fraction form
    10.40/14.31 = 8.57/x
  3. Step 3: Cross multiply
    10.40x = 14.31 × 8.57
  4. Step 4: Simplify right side
    10.40x = 122.67
  5. Step 5: Solve for x
    x = 122.67/10.40
  6. Step 6: Final answer
    x = 11.80

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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.