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Finding the Fourth Proportional to 688.62, 1,032.20 and 428.62

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Solution

The fourth proportional to 688.62, 1,032.20 and 428.62 is: 642.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.62 : 1,032.20 = 428.62 : x
  2. Step 2: Convert to fraction form
    688.62/1,032.20 = 428.62/x
  3. Step 3: Cross multiply
    688.62x = 1,032.20 × 428.62
  4. Step 4: Simplify right side
    688.62x = 442,421.56
  5. Step 5: Solve for x
    x = 442,421.56/688.62
  6. Step 6: Final answer
    x = 642.48

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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.