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Finding the Fourth Proportional to 202.78, 279.81 and 128.98

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Solution

The fourth proportional to 202.78, 279.81 and 128.98 is: 177.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    202.78 : 279.81 = 128.98 : x
  2. Step 2: Convert to fraction form
    202.78/279.81 = 128.98/x
  3. Step 3: Cross multiply
    202.78x = 279.81 × 128.98
  4. Step 4: Simplify right side
    202.78x = 36,089.89
  5. Step 5: Solve for x
    x = 36,089.89/202.78
  6. Step 6: Final answer
    x = 177.98

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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.