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Finding the Fourth Proportional to 10.40, 14.25 and 9.78

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Solution

The fourth proportional to 10.40, 14.25 and 9.78 is: 13.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.40 : 14.25 = 9.78 : x
  2. Step 2: Convert to fraction form
    10.40/14.25 = 9.78/x
  3. Step 3: Cross multiply
    10.40x = 14.25 × 9.78
  4. Step 4: Simplify right side
    10.40x = 139.37
  5. Step 5: Solve for x
    x = 139.37/10.40
  6. Step 6: Final answer
    x = 13.41

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.