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Finding the Fourth Proportional to 40.78, 61.14 and 13.72

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Solution

The fourth proportional to 40.78, 61.14 and 13.72 is: 20.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.78 : 61.14 = 13.72 : x
  2. Step 2: Convert to fraction form
    40.78/61.14 = 13.72/x
  3. Step 3: Cross multiply
    40.78x = 61.14 × 13.72
  4. Step 4: Simplify right side
    40.78x = 838.84
  5. Step 5: Solve for x
    x = 838.84/40.78
  6. Step 6: Final answer
    x = 20.57

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.