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Finding the Fourth Proportional to 10.47, 15.78 and 9

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Solution

The fourth proportional to 10.47, 15.78 and 9 is: 13.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.47 : 15.78 = 9 : x
  2. Step 2: Convert to fraction form
    10.47/15.78 = 9/x
  3. Step 3: Cross multiply
    10.47x = 15.78 × 9
  4. Step 4: Simplify right side
    10.47x = 142.02
  5. Step 5: Solve for x
    x = 142.02/10.47
  6. Step 6: Final answer
    x = 13.56

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.