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Finding the Fourth Proportional to 426.65, 639.78 and 221.01

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Solution

The fourth proportional to 426.65, 639.78 and 221.01 is: 331.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.65 : 639.78 = 221.01 : x
  2. Step 2: Convert to fraction form
    426.65/639.78 = 221.01/x
  3. Step 3: Cross multiply
    426.65x = 639.78 × 221.01
  4. Step 4: Simplify right side
    426.65x = 141,399.35
  5. Step 5: Solve for x
    x = 141,399.35/426.65
  6. Step 6: Final answer
    x = 331.42

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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.