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Finding the Fourth Proportional to 142.06, 212.89 and 81.11

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Solution

The fourth proportional to 142.06, 212.89 and 81.11 is: 121.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.06 : 212.89 = 81.11 : x
  2. Step 2: Convert to fraction form
    142.06/212.89 = 81.11/x
  3. Step 3: Cross multiply
    142.06x = 212.89 × 81.11
  4. Step 4: Simplify right side
    142.06x = 17,267.51
  5. Step 5: Solve for x
    x = 17,267.51/142.06
  6. Step 6: Final answer
    x = 121.55

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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.