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Finding the Fourth Proportional to 265.76, 398.64 and 128.80

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Solution

The fourth proportional to 265.76, 398.64 and 128.80 is: 193.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    265.76 : 398.64 = 128.80 : x
  2. Step 2: Convert to fraction form
    265.76/398.64 = 128.80/x
  3. Step 3: Cross multiply
    265.76x = 398.64 × 128.80
  4. Step 4: Simplify right side
    265.76x = 51,344.83
  5. Step 5: Solve for x
    x = 51,344.83/265.76
  6. Step 6: Final answer
    x = 193.20

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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.