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Finding the Fourth Proportional to 280.29, 420.41 and 74.86

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Solution

The fourth proportional to 280.29, 420.41 and 74.86 is: 112.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.29 : 420.41 = 74.86 : x
  2. Step 2: Convert to fraction form
    280.29/420.41 = 74.86/x
  3. Step 3: Cross multiply
    280.29x = 420.41 × 74.86
  4. Step 4: Simplify right side
    280.29x = 31,469.88
  5. Step 5: Solve for x
    x = 31,469.88/280.29
  6. Step 6: Final answer
    x = 112.28

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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.