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Finding the Fourth Proportional to 40.78, 61.16 and 19.11

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Solution

The fourth proportional to 40.78, 61.16 and 19.11 is: 28.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.78 : 61.16 = 19.11 : x
  2. Step 2: Convert to fraction form
    40.78/61.16 = 19.11/x
  3. Step 3: Cross multiply
    40.78x = 61.16 × 19.11
  4. Step 4: Simplify right side
    40.78x = 1,168.67
  5. Step 5: Solve for x
    x = 1,168.67/40.78
  6. Step 6: Final answer
    x = 28.66

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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.