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Finding the Fourth Proportional to 272.70, 408.78 and 128.25

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Solution

The fourth proportional to 272.70, 408.78 and 128.25 is: 192.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    272.70 : 408.78 = 128.25 : x
  2. Step 2: Convert to fraction form
    272.70/408.78 = 128.25/x
  3. Step 3: Cross multiply
    272.70x = 408.78 × 128.25
  4. Step 4: Simplify right side
    272.70x = 52,426.04
  5. Step 5: Solve for x
    x = 52,426.04/272.70
  6. Step 6: Final answer
    x = 192.25

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.