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Finding the Fourth Proportional to 201.80, 278.49 and 128.10

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Solution

The fourth proportional to 201.80, 278.49 and 128.10 is: 176.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    201.80 : 278.49 = 128.10 : x
  2. Step 2: Convert to fraction form
    201.80/278.49 = 128.10/x
  3. Step 3: Cross multiply
    201.80x = 278.49 × 128.10
  4. Step 4: Simplify right side
    201.80x = 35,674.57
  5. Step 5: Solve for x
    x = 35,674.57/201.80
  6. Step 6: Final answer
    x = 176.78

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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.