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Finding the Fourth Proportional to 280.26, 420.39 and 261.77

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Solution

The fourth proportional to 280.26, 420.39 and 261.77 is: 392.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.26 : 420.39 = 261.77 : x
  2. Step 2: Convert to fraction form
    280.26/420.39 = 261.77/x
  3. Step 3: Cross multiply
    280.26x = 420.39 × 261.77
  4. Step 4: Simplify right side
    280.26x = 110,043.39
  5. Step 5: Solve for x
    x = 110,043.39/280.26
  6. Step 6: Final answer
    x = 392.65

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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.