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Finding the Fourth Proportional to 201.79, 278.34 and 128.16

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Solution

The fourth proportional to 201.79, 278.34 and 128.16 is: 176.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    201.79 : 278.34 = 128.16 : x
  2. Step 2: Convert to fraction form
    201.79/278.34 = 128.16/x
  3. Step 3: Cross multiply
    201.79x = 278.34 × 128.16
  4. Step 4: Simplify right side
    201.79x = 35,670.79
  5. Step 5: Solve for x
    x = 35,670.79/201.79
  6. Step 6: Final answer
    x = 176.77

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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.