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Finding the Fourth Proportional to 265.85, 398.88 and 128.91

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Solution

The fourth proportional to 265.85, 398.88 and 128.91 is: 193.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    265.85 : 398.88 = 128.91 : x
  2. Step 2: Convert to fraction form
    265.85/398.88 = 128.91/x
  3. Step 3: Cross multiply
    265.85x = 398.88 × 128.91
  4. Step 4: Simplify right side
    265.85x = 51,419.62
  5. Step 5: Solve for x
    x = 51,419.62/265.85
  6. Step 6: Final answer
    x = 193.42

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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.