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Finding the Fourth Proportional to 142.05, 212.25 and 128.55

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Solution

The fourth proportional to 142.05, 212.25 and 128.55 is: 192.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.05 : 212.25 = 128.55 : x
  2. Step 2: Convert to fraction form
    142.05/212.25 = 128.55/x
  3. Step 3: Cross multiply
    142.05x = 212.25 × 128.55
  4. Step 4: Simplify right side
    142.05x = 27,284.74
  5. Step 5: Solve for x
    x = 27,284.74/142.05
  6. Step 6: Final answer
    x = 192.08

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.