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Finding the Fourth Proportional to 638.95, 881.76 and 428.80

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Solution

The fourth proportional to 638.95, 881.76 and 428.80 is: 591.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.95 : 881.76 = 428.80 : x
  2. Step 2: Convert to fraction form
    638.95/881.76 = 428.80/x
  3. Step 3: Cross multiply
    638.95x = 881.76 × 428.80
  4. Step 4: Simplify right side
    638.95x = 378,098.69
  5. Step 5: Solve for x
    x = 378,098.69/638.95
  6. Step 6: Final answer
    x = 591.75

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.