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Finding the Fourth Proportional to 688.16, 1,027.28 and 639.56

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Solution

The fourth proportional to 688.16, 1,027.28 and 639.56 is: 954.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.16 : 1,027.28 = 639.56 : x
  2. Step 2: Convert to fraction form
    688.16/1,027.28 = 639.56/x
  3. Step 3: Cross multiply
    688.16x = 1,027.28 × 639.56
  4. Step 4: Simplify right side
    688.16x = 657,007.20
  5. Step 5: Solve for x
    x = 657,007.20/688.16
  6. Step 6: Final answer
    x = 954.73

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.