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Finding the Fourth Proportional to 202.42, 279.14 and 128.78

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Solution

The fourth proportional to 202.42, 279.14 and 128.78 is: 177.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    202.42 : 279.14 = 128.78 : x
  2. Step 2: Convert to fraction form
    202.42/279.14 = 128.78/x
  3. Step 3: Cross multiply
    202.42x = 279.14 × 128.78
  4. Step 4: Simplify right side
    202.42x = 35,945.61
  5. Step 5: Solve for x
    x = 35,945.61/202.42
  6. Step 6: Final answer
    x = 177.58

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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.