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Finding the Fourth Proportional to 280.13, 420.27 and 85.12

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Solution

The fourth proportional to 280.13, 420.27 and 85.12 is: 127.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.13 : 420.27 = 85.12 : x
  2. Step 2: Convert to fraction form
    280.13/420.27 = 85.12/x
  3. Step 3: Cross multiply
    280.13x = 420.27 × 85.12
  4. Step 4: Simplify right side
    280.13x = 35,773.38
  5. Step 5: Solve for x
    x = 35,773.38/280.13
  6. Step 6: Final answer
    x = 127.70

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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.