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Finding the Fourth Proportional to 142.92, 214.71 and 85.29

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Solution

The fourth proportional to 142.92, 214.71 and 85.29 is: 128.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.92 : 214.71 = 85.29 : x
  2. Step 2: Convert to fraction form
    142.92/214.71 = 85.29/x
  3. Step 3: Cross multiply
    142.92x = 214.71 × 85.29
  4. Step 4: Simplify right side
    142.92x = 18,312.62
  5. Step 5: Solve for x
    x = 18,312.62/142.92
  6. Step 6: Final answer
    x = 128.13

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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.