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Finding the Fourth Proportional to 202.09, 278.84 and 128.42

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Solution

The fourth proportional to 202.09, 278.84 and 128.42 is: 177.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    202.09 : 278.84 = 128.42 : x
  2. Step 2: Convert to fraction form
    202.09/278.84 = 128.42/x
  3. Step 3: Cross multiply
    202.09x = 278.84 × 128.42
  4. Step 4: Simplify right side
    202.09x = 35,808.63
  5. Step 5: Solve for x
    x = 35,808.63/202.09
  6. Step 6: Final answer
    x = 177.19

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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.