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Finding the Fourth Proportional to 280.86, 421.40 and 143.79

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Solution

The fourth proportional to 280.86, 421.40 and 143.79 is: 215.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.86 : 421.40 = 143.79 : x
  2. Step 2: Convert to fraction form
    280.86/421.40 = 143.79/x
  3. Step 3: Cross multiply
    280.86x = 421.40 × 143.79
  4. Step 4: Simplify right side
    280.86x = 60,592.39
  5. Step 5: Solve for x
    x = 60,592.39/280.86
  6. Step 6: Final answer
    x = 215.74

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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.