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Finding the Fourth Proportional to 688.20, 1,032.30 and 428.94

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Solution

The fourth proportional to 688.20, 1,032.30 and 428.94 is: 643.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.20 : 1,032.30 = 428.94 : x
  2. Step 2: Convert to fraction form
    688.20/1,032.30 = 428.94/x
  3. Step 3: Cross multiply
    688.20x = 1,032.30 × 428.94
  4. Step 4: Simplify right side
    688.20x = 442,794.76
  5. Step 5: Solve for x
    x = 442,794.76/688.20
  6. Step 6: Final answer
    x = 643.41

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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.