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Finding the Fourth Proportional to 426.87, 640.31 and 280.67

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Solution

The fourth proportional to 426.87, 640.31 and 280.67 is: 421.00

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.87 : 640.31 = 280.67 : x
  2. Step 2: Convert to fraction form
    426.87/640.31 = 280.67/x
  3. Step 3: Cross multiply
    426.87x = 640.31 × 280.67
  4. Step 4: Simplify right side
    426.87x = 179,711.20
  5. Step 5: Solve for x
    x = 179,711.20/426.87
  6. Step 6: Final answer
    x = 421.00

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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.