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Finding the Fourth Proportional to 9.78, 14.73 and 8.72

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Solution

The fourth proportional to 9.78, 14.73 and 8.72 is: 13.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    9.78 : 14.73 = 8.72 : x
  2. Step 2: Convert to fraction form
    9.78/14.73 = 8.72/x
  3. Step 3: Cross multiply
    9.78x = 14.73 × 8.72
  4. Step 4: Simplify right side
    9.78x = 128.40
  5. Step 5: Solve for x
    x = 128.40/9.78
  6. Step 6: Final answer
    x = 13.13

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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.