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Finding the Fourth Proportional to 142.09, 212.86 and 81.03

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Solution

The fourth proportional to 142.09, 212.86 and 81.03 is: 121.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.09 : 212.86 = 81.03 : x
  2. Step 2: Convert to fraction form
    142.09/212.86 = 81.03/x
  3. Step 3: Cross multiply
    142.09x = 212.86 × 81.03
  4. Step 4: Simplify right side
    142.09x = 17,248.95
  5. Step 5: Solve for x
    x = 17,248.95/142.09
  6. Step 6: Final answer
    x = 121.40

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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.