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Finding the Fourth Proportional to 426.88, 640.40 and 221.40

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Solution

The fourth proportional to 426.88, 640.40 and 221.40 is: 332.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.88 : 640.40 = 221.40 : x
  2. Step 2: Convert to fraction form
    426.88/640.40 = 221.40/x
  3. Step 3: Cross multiply
    426.88x = 640.40 × 221.40
  4. Step 4: Simplify right side
    426.88x = 141,784.56
  5. Step 5: Solve for x
    x = 141,784.56/426.88
  6. Step 6: Final answer
    x = 332.14

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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.