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Finding the Fourth Proportional to 665.50, 998.25 and 280.78

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Solution

The fourth proportional to 665.50, 998.25 and 280.78 is: 421.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.50 : 998.25 = 280.78 : x
  2. Step 2: Convert to fraction form
    665.50/998.25 = 280.78/x
  3. Step 3: Cross multiply
    665.50x = 998.25 × 280.78
  4. Step 4: Simplify right side
    665.50x = 280,288.64
  5. Step 5: Solve for x
    x = 280,288.64/665.50
  6. Step 6: Final answer
    x = 421.17

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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.