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Finding the Fourth Proportional to 268.57, 402.57 and 85.91

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Solution

The fourth proportional to 268.57, 402.57 and 85.91 is: 128.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    268.57 : 402.57 = 85.91 : x
  2. Step 2: Convert to fraction form
    268.57/402.57 = 85.91/x
  3. Step 3: Cross multiply
    268.57x = 402.57 × 85.91
  4. Step 4: Simplify right side
    268.57x = 34,585.04
  5. Step 5: Solve for x
    x = 34,585.04/268.57
  6. Step 6: Final answer
    x = 128.78

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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.