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Finding the Fourth Proportional to 688, 1,031.82 and 399.64

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Solution

The fourth proportional to 688, 1,031.82 and 399.64 is: 599.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    688 : 1,031.82 = 399.64 : x
  2. Step 2: Convert to fraction form
    688/1,031.82 = 399.64/x
  3. Step 3: Cross multiply
    688x = 1,031.82 × 399.64
  4. Step 4: Simplify right side
    688x = 412,356.54
  5. Step 5: Solve for x
    x = 412,356.54/688
  6. Step 6: Final answer
    x = 599.36

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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.