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Finding the Fourth Proportional to 280.72, 387.41 and 156.39

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Solution

The fourth proportional to 280.72, 387.41 and 156.39 is: 215.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.72 : 387.41 = 156.39 : x
  2. Step 2: Convert to fraction form
    280.72/387.41 = 156.39/x
  3. Step 3: Cross multiply
    280.72x = 387.41 × 156.39
  4. Step 4: Simplify right side
    280.72x = 60,587.05
  5. Step 5: Solve for x
    x = 60,587.05/280.72
  6. Step 6: Final answer
    x = 215.83

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.