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Finding the Fourth Proportional to 280.57, 420.87 and 199.78

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Solution

The fourth proportional to 280.57, 420.87 and 199.78 is: 299.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.57 : 420.87 = 199.78 : x
  2. Step 2: Convert to fraction form
    280.57/420.87 = 199.78/x
  3. Step 3: Cross multiply
    280.57x = 420.87 × 199.78
  4. Step 4: Simplify right side
    280.57x = 84,081.41
  5. Step 5: Solve for x
    x = 84,081.41/280.57
  6. Step 6: Final answer
    x = 299.68

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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.