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Finding the Fourth Proportional to 101.78, 140.42 and 79.91

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Solution

The fourth proportional to 101.78, 140.42 and 79.91 is: 110.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.78 : 140.42 = 79.91 : x
  2. Step 2: Convert to fraction form
    101.78/140.42 = 79.91/x
  3. Step 3: Cross multiply
    101.78x = 140.42 × 79.91
  4. Step 4: Simplify right side
    101.78x = 11,220.46
  5. Step 5: Solve for x
    x = 11,220.46/101.78
  6. Step 6: Final answer
    x = 110.25

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.