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Finding the Fourth Proportional to 688.50, 1,032.96 and 399.78

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Solution

The fourth proportional to 688.50, 1,032.96 and 399.78 is: 599.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.50 : 1,032.96 = 399.78 : x
  2. Step 2: Convert to fraction form
    688.50/1,032.96 = 399.78/x
  3. Step 3: Cross multiply
    688.50x = 1,032.96 × 399.78
  4. Step 4: Simplify right side
    688.50x = 412,956.75
  5. Step 5: Solve for x
    x = 412,956.75/688.50
  6. Step 6: Final answer
    x = 599.79

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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.