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Finding the Fourth Proportional to 371.88, 557.91 and 128.40

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Solution

The fourth proportional to 371.88, 557.91 and 128.40 is: 192.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    371.88 : 557.91 = 128.40 : x
  2. Step 2: Convert to fraction form
    371.88/557.91 = 128.40/x
  3. Step 3: Cross multiply
    371.88x = 557.91 × 128.40
  4. Step 4: Simplify right side
    371.88x = 71,635.64
  5. Step 5: Solve for x
    x = 71,635.64/371.88
  6. Step 6: Final answer
    x = 192.63

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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.